Is it possible to have leftover extra keys for some dungeons?

[alienstookmybeer]

I still had 1 key left for the "dungeon" area that has the elevator that can take you to 4 different floors. I painstakingly backtracked through much of the area but couldn't find a place to use the last key.

Was wondering if they might have stuck an extra key in here to prevent people getting stuck if the keys were used in an less than ideal order?

[Räsvelg AtmaYantra N4]

Yeah, the hotel dungeon has 1 extra key, I wouldn't worry about it. I went back to it after beating the game and explored all possible OOB areas, and there doesn't seem to be any extra key door.