The key is located in Shanty Town in the Graveyard Shift Bar.
Enter the bar: (sign above says "Welcome to the Graveyard Shift")
Take the door on the far end to the right:
Go down the stairs to the basement and pick up the keys, on one of the barrels in the corner opposite the guitar:
Enter the Bull House Impound
Inside the Bullhouse Impound climb the stairs to the second floor:
Enter this room:
Near the drawers there is an entrance to the room with a chest:
Find the chest near the table:
