Not in questions like this one. This det is a formal subject so it does not change with the noun, it's like it in 'It's raining', it's just there as a placeholder.
So if you ask if there is any food, which is an en word, it would still be Finns det (någon) mat 'Is there (any) food'.
In other contexts, den/det may be a pronoun instead of a formal subject, and in those cases it changes with the noun. Like, Var är kaffet? Finns det här? ('Where is the coffee? Is it here?') vs Var är maten? Finns den här? ('Where is the food? Is it here?'). I think this matches the difference between is there and is it in English pretty well, so it shouldn't be difficult for you if you already know English.