First, I'd want to know where the ants came from and how did they get in the snakes enclosure ?
For them to completely cover a dead mouse in only an hour, there has to be a lot of them, and they had to have been in that area for a while. Ants do send out scouts looking for food, but it take many hours or even days for them to find food that way unless you drop it on an established ant trail.
Do not leave your snake in with the ants. While they may not be capable of harming him through his scales, they will find his delicate eyes, nostrils, mouth and vent and could do serious damage. The fastest way to get rid of them temporarily is dump any bedding in the enclosure out, then stick the whole thing in the shower to wash them away.
This is only a temporary fix however, because more will quickly follow the established scent trail and invade his cage again. If you don't have any bug killer in the house you could spray on a towel and wipe all around where his cage sits, sprinkle cinnamon around it as a stop-gap measure until you can get the bug killer.
Please take care of this now, not later. I understand the need for sleep before work, but that is what 5 hour Energy is for!!
Gale