From Practical English Usage by Michael Swan:
"Any is very often used with uncountable nouns and plural nouns. It can have the same kind of meaning as the indefinite article a/an has with singular countable nouns. E.g.: I haven't got a car, and I haven't got any money to buy one.
Is there a tin-opener in the house? And are there any plates?
With this meaning any is unusual with singular countable nouns.
She hasn't got a job. - NOT, She hasn't got any job.
Do you know a good doctor? - NOT, Do you know any good doctor?
With an uncountable noun or plural noun, any usually suggests the idea of an indefinite amount or indefinite number. When there is no idea of quantity or number, no article is used.
Is there any water in that can?
Is there water on the moon?
Any can be used to emphasise the idea of 'free choice', with the meaning of 'it doesn't matter who/which/what'. With this meaning, any is common in affirmative clauses as well as questions and negatives, and is often used with singular countable nouns as well as uncountables and plurals."