How long does yeast live after baking?
Yeast dies at about 130-140F.

Bread is done baking at 200F or so.

Almost all the yeast is dead when the bread is done.

Edit
I wrote "almost" because in the context of cooking nothing is ever 100%. Not all alcohol boils it off a sauce. Not all microbes are killed. Etc.

The longer and hotter you cook the more are killed until there are too few to be an issue. We're content if 99.99% of bacteria or yeast are dead - but there are always a few that survive.

As an example- Russian kvass is made by putting well toasted black bread in water with a little sugar until it is carbonated. There is enough yeast alive in the bread even after baking and well toasting.