The MAF sensor itself doesn't require a burn-off cycle like some other sensors. Any power to the MAF sensor would come from a fused circuit protected by an inline fuse, not a specific relay dedicated to a burn-off function. To find the circuit for the MAF sensor, you'd need to consult a wiring diagram specific to your 1988 Corvette's engine (L98 or some other variant). This diagram will show the fuse and the power source.
If you're troubleshooting a problem, describing the symptom rather than using this incorrect terminology would be helpful in finding the actual problem.