Buy some bread, tomatoes, cucumber, mayo and cold cuts from any of the supermarkets and make your own sandwich

or

you can buy some readymade food from Safari Supermarket any time.  (last week at 10am, I picked up some pretty good biryani from them)  FFC Rayyan and airport sells food after 1230

or

pick up some precooked food from the freezer section of FFC, Lulu and put it in the Micro