First find out what it is worth to a collector.
The box may be worth quite a bit since it is unopened.
That being said .22 LR ammo does seem to be more temperamental about how it was stored. However, you won't know if it is good until you try.
BTW, I have a friend who's grandpa died and I helped him clean out the garage. I've seen ammo stored in a chest since WWII work just fine. No hang fires or anything from the .45acp.
The 1911 we did find was rusted up pretty bad, cocked and locked with one in the chamber.
It needed to be cleaned up, a new barrel and magazine and all new springs, and although the slide is pitted it still works today.