Ilja gives me the temple key and says he wants a vase in return for it.

how much time do i have to get him the vase? He says aomething about assassins after me.

Can i just take the key and give him the vase whenever im ready or do i have to hurry up to avoid some negative consequences?

I don't think it's a timed quest, as all of those should have something like "Days left: X" (like, for example, the one in which you have to report to Marik). Anyway, I never got punished, but I usually didn't waste too much time before cleaning the temple.

thank you :)