It is located near right elevator going down to Duty Free. Mcdonalds food court is between two elevators. You won't notice it. you will see only a computer and attendant like check-in counter and there is small enterance next to him which takes you to this nice restaurant.
You can also read here under food and drinks:
http://ezinearticles.com/?How-to-Mak...ort&id=2078985
In fact, the place is never crowded as not many people know this.
A lot of food choices and off course, Emirates standard. Eat as much as you want!