The 1885 citation is Muskerry & Jourdain's Khartoum! ("Ha! they're here. Ah, curses!") because Etymonline got this information from the OED. However, this particular OED article hasn't been updated.
I've been able to find some examples that are much, much earlier, with the earliest one being from 1684:
Curses and Vengeance. Married! say by whom?
Oh Curses! Vengeance! Curses yet unthought!
Such Curses as thou wilt let fly at me,
When thou shalt see his Head beneath the Ax,
Even Womans Curses on thee.
Constantine the great
Then there are two other early examples both written by Mary Pix. The first one is from 1698:
Curses, curses! Oh Malavill, in thy bosom
Hide me, for if I look that way my eyes will burst.
The second one is from 1700:
What, to be Answer'd as I was last: If I wou'd be his Bailiff, I might eat: Curses, I'de sooner feed on my own Flesh! Sue to him, who never knew
Curses, Curses, Ah I shall Choak.
The beau defeated
I also found an example from 1801:
Curses! curses! oh! what pain!
How my melting eyeballs glow!
Curses! curses! through each vein!
How do boiling torrents flow!
The Sword of Angantyr
There are some other examples from the 1800s. Here's a link to one from 1842: The Metropolitan.
Grammarphobia has examples from 1839 and 1843.