If the universe is infinite in size, the universe will reach maximum entropy (equilibrium) when time = infinity. It is not possible to have finite entropy in an infinite universe. Maximum entropy occurs when the whole universe is filled up with an equal density of matter, but if the universe is infinite, matter needs to expand forever to reach equilibrium.

However, if the universe ends in a big crunch, then the maximum achievable entropy will be at the end of the big crunch when the universe is just 1 superheavy black hole/singularity (as black holes have very high values of entropy).

"I have great faith in fools; self-confidence my friends call it."

-Edgar Allan Poe