Of course the real question here is: what brand is it?
Answer that and we can tell you if it is safe to eat, expired, or fresh.
Also if it is moving, don't eat it. First kill it, then eat it. Use fire to kill it, that saves cooking time. You can apply this principle to many creatures, not just evolved protein tubs.
But more seriously, a closet would have helped keep it fresh. If you were in a warm climate, that might degrade it faster. But it isn't going to be lethal, maybe 5% diminished potency.
If there was moisture in it though, that ain't so good.
I've got protein in my cupboard from 1999 ... I dunno if it is OK I have not opened it. I doubt it.