Sadly this game bugged out quite a bit after I went downstairs where the keypad was. My mouse kept bugging out of the game and leaving the screen. And when I did go downstairs after Krabs died, the notification in the top left bugged out and I couldn't see what it said.
I found the key and saw a box with a lock on it, but there was no command what-so-ever to even use the key to open it.
I kept restarting the game to see if it would fix it and it didn't work.