" So I go to get my dust pan from the hall closet the other day and guess what? I can't find my stupid keys. It's like they disappeared into thin air or something. "
Wally talking about losing his keys, Chapter 2
keys are an item that Henry must find in order to open the hall closet in of Chapter 2 .
Bendy and the Ink Machine
Wally Franks' voice from his second audio log near from the door leading to Sammy's office implies that the keys can be found in one of the garbage cans.
They are two identical keys attached to a keyring. Each has three notches, two that are thin and one that is thicker, with an added square. Overall, they are a light tan color.
The keys can be found in one of four garbage cans at the
Music Department hall as well as its entrance. They can be also found in the music writing room, and the Balcony.
The keys were left in the trash bin for 30 years, according to theMeatly.
 The keys' pop-up icon appears on the menu of the released chapter when they are not purchased.
When the player takes the keys, they make a "picked up" animation like the items for the break room's pedestals. This is along with other items that have have this animation.
The sound produced when the keys are collected.
Key's texture map along with other items.
Ditto, but bigger and tilted at a different angle.
Why would Wally leave his keys in the trash for 30 years? It's almost as if he never got a chance to go back for them..." - theMeatly. June 25, 2017. Twitter.