Immigrations if you're lucky can be 2-3 minutes. If you're not, 15-20 maybe. If you're travelling in business and get a Fast Track card, don't assume that it is faster than the standard queue - just pick whichever looks shorter. Customs is usually 0 minutes as you just walk straight through the green channel.
Any of the hotels on Yas island will be within 15 minutes of the airport for you.