Boys' Shower Room Key (Hangul: 남샤워실열쇠) is a scrapped/removed Key item in the final version of the game.
Like the other removed items, it cannot be found in any buildings and it can only be added through the use of Console Commands.
It is used on the glass doors in the Boys' Shower Room.
(Keyhole at the bottom.)
However, the glass door is already open.