An answer by Colin Fine to the duplicate question What’s the origin of the phrase “pay attention”? Did one have to pay monies for this historically? reports that the earliest instance of "pay attention" in the Corpus of Historical American English is from 1822. I have found a number of instances from England and Scotland that are considerably older than that. Here are the ten earliest unique matches that I found through various database searches:
From "Advices from Holland," in The Political State of Great Britain, volume 53 (1737):
In the Month of July we received Advice that the States-General, press'd by the Ministers of the Emperor and France to give a positive Answer, one Way or other, to the Instances so often repeated, for obtaining their High Mightinesses Guaranty, together with that of Great Britain, with Regard to the new Disposition of Affairs, as settled between their Imperial and most Christian Majesties, are at last come to a Resolution, which has been communicated in Form to the said two Ministers, and, as they write from the Hague, contains in Purport as follows: 'That the States General, to comply as far as in them lies with the Intentions of their Imperial and most Christian Majesties, have not insisted upon several Articles which they might, with Reason, have hop'd to see comprized in the Negociations some Time carry'd on between the Courts of Vienna and France, but that the said Negociations being now on the Point of determining, their High Mightinesses expect that their Imperial and most Christian Majesties will pay Attention to the Representations and Demands which the King of Great-Britain, jointly with the Republick, has made to them, in order to have proper Articles with Regard thereto, inserted in the General Treaty of Peace.'
Essentially the same text appeared in the "Ipswich [Suffolk] Journal (July 24, 1736), and in other English newspapers at around the same date.
From a letter from Glasgow, in "Reflexions on Honour," in The Scots Magazine (March 1745):
He [a man of honour] stands high and supereminent upon the foundations of true greatness of soul, and unshaken generosity of temper: he embraces and patronizes every thing that is worthy, amiable, and exalted; and pays attention and regard to what may most improve, embellish, and dignify him ; and walks with an unwearied pace in the shining sublime road of excellence and distinction ; and, in fine, his imagination smiles with the agreeable expectation of standing fair in the opinion of the world, sparkles with the joyful prospect of being emtomb'd in the sepulchre of fame, of being embalmed in the memories of the wise, and enshrined in the hearts of the good and virtuous.
From a letter from G.F. Gaupp, dated February 20, 1754, in "Fort St. George, March 1754," in Records of Fort St. George: Diary and Consultation Book, volume 82 (1754):
[A]s an officer who piques himself on applying all his attention and attachment to his Duty and the service cannot look into this little detail of his affairs, I have the more reason to hope that my Masters will secure me from Ruin and order that Gratification for the Cloathing stipulated in the agreement, be paid completely for the whole year for the same number of Men as were clothed on their arrival on the Coast. I venture to flatter myself you will pay attention to my Request and I put my whole confidence in your goodness.
From a review of Philosophical Transactions ... for the Year 1753 in The Monthly Review (September 1754):
Should any member of this learned body produce an improvement in the construction of so common a culinary utensil, as a pair of bellows, how heartily would he be laughed at for his pains by these superficial critics! and the society too, had they paid attention to his communication. But should this improvement be adapted to those larger machines of the same kind, without which, many of our capital works cannot be carried on; should it be found, that it saved time, fuel, and labour, and consequently turned out a considerable annual advantage to the nation, the philosophical bellows-maker would no longer be an object of ridicule ; intitled, as he would stand, to the honour and reward of his ingenuity.
From Samuel Johnson, A Dictionary of the English Language,volume 2 (1755):
To REGARD. ... 5. To pay attention to.
From J.G., "Faction's Overthrow: Or, More Fair Warning and Good Advice to the Nobility, Gentry, and Commonalty of Ireland" (1755):
I will not, at present, detain you with commenting on my last Paper of national Grievances ; some future Opportunity I may resume the Subject. Do not pay Attention, my dear Friends, to this wicked Dionysius, or his Associates ; I have demonstrated to you the Badness of their Intentions, and illustrated his Character, in particular, with repeated Quotations from 1749, a Case which you must all see is exactly parallel to our present one.
From "Fort St. George, October 1755, in Records of Fort St. George (1755):
Letter [dated October 3, 1755] from Colonel Heron refusing to pay Attention to the Secretary's Letter to him acquainting him of his Suspension from his Seat at the Board.
Honble Sir & Sirs
I have received a Letter (dated the 29th. Septr.) from your Secretary Mr. Du Pre acquainting me with being suspended from my seat in Council [.] But as I have no Concerns with him and you frequently sign General Letters of less consequence, I cannot think of paying any Attention to such an Order of Suspension unless signed by the whole Council.
I am Honble Sir & Sirs Your most Obedient humble servt. Alexr. Heron
From "London," the Newcastle [Northumberland] Courant (September 18, 1756) [combined snippets]:
By extending it the smaller Towns and Villages, which, Doubt, the Proprietor will take proper Methods to do; its Utility will thereby be more universally experienced: And although the present annual Expence for the Article of Blue to each Family may be small, which, perhaps may make it [a] trifling Consideration for Particulars pay Attention to; yet, when the Nature and Merits of the BRITISH BLUE are considered, and the Benefits arising to the Community, by substituting in the Room of Foreign Commodities a Manufacture of our own; few Articles will be found to claim a greater Regard.
And from The Con-Test, Number 5 (December 18, 1756):
But not to rely solely on past experience, we will attempt to assign reasons why naval affairs should miscarry under the administration of a president supposed to be thoroughly conversant in maritime concerns, and prosper under the direction of one less experienced.—The former considers himself as acting in his profession, and brings to the board with him, strong presumption, dogmatic pre-judgment, and a disregard for the opinion of his colleagues : But the latter, not being swayed by the vanity of particular naval excellence, gladly receives information from every one, and having paid attention to their respective propositions, he will find it no difficult matter to make a proper determination.
From a review of The Fatal Consequences of the Want of System in the Conduct of Public Affairs, in The Critical Review, or Annals of Literature (December 1756):
All that we can gather from the harsh, ungrateful stile, and long-winded periods of this performance, is that ministerial influence, operating through all the public offices, may produce a dangerous dependency and confusion in the national accompts. That all the public offices ought to center in the sovereign. That the method of transacting affairs in council, has undergone divers revolutions since the reign of Henry VII. That regular reports of the proceedings in council, ought to be laid before his Majesty ; and that it will be impossible for any administration to support the dignity o the crown, or pay attention to the concerns of the nation, unless they have recourse to the first principles of the constitution, by renewing the system of the public boards, and by establishing the general course of the said boards by law.
To sum up these results, we have one match from 1736–1737, one from 1745, two from 1754, three from 1755 (including one that appears in Samuel Johnson's dictionary), and three from 1756.The source countries are England (six), India (two), Scotland (one), and Ireland (one). The earliest match from the United States in an Elephind database search i from "Louisville, Jan. 4," in the [Vincennes, Indiana] Western Sun (February 4, 1809):
The present fresh [rise in the Ohio River) has been accompanied with the severest cold of our winters, which rendered it peculiarly distressing to those whose property lay within the reach of th flood. The whole plain from Louisville to Shippingsport, below the second bank, was inundated and the streets of Shippingsport were navigable for boats, but as there was no current there was no material injury or loss of property sustained, except what arose from the improvidence of those who did not pay attention to the safety of their Cattle, and Hogs &c.
It should be noted that most of the U.S. newspaper archives that Elephind searches do not go back much farther than 1800. Still, on the evidence available to me it appears that "pay attention" arose as an English expression in Great Britain, probably in the early 1730s, and began to gain widespread use in published writing in the 1750s, also initially in Great Britain.