What will happen if you pour an asphalt sealer over a concrete driveway?

You will get a thin layer of asphalt or epoxy (if it is an epoxy type sealer) on top of your concrete.

I wouldn’t expect a great finish as most asphalt sealers expect asphalt beneath them. It will probably grab well in some places but not in others. Also, it will probably stain your concrete badly.

Imagine burnt marshmallow smeared over your concrete. You have a 50% chance of facing that scenario.