I don't know anything about losing keys?
The servers continue to be shit, so unless you happen to be playing during the few moments when shit works, you'll have trouble getting fights to complete. But keys shouldn't be lost, as long as you resume after every Nike? In other words, as long as you don't need timer-based debuffs and have extreme patience, doing them today should work out.
Then again if you have Medea, you can just wait and hope for a better day. Up to you.