Is the little red light on both keys flashing when the unlock/lock button is pressed? If not, try replacing the key battery. Although it seems unlikely that both keys have died at the same time.
Have you tried re-synchronising the keys?
If all that fails, do you have TOAF diagnostic software? You could scan the BCU (Body Control Unit) and see which keys are registered and campare to the labels stuck to the circuit boards within the the key fobs.