I dont have a Koala I have a Horn cabinet..so dont know if they are similar..
I just looked at mine and depending on the construction of your cabinet you might be able to try this..
On my Horn underneath there is no panel and if i was desperate like you I would be able to slide under some timber and get it higher off the floor then you could slide in there and unscrew the lock from the inside..on my Horn there are screws... again I dont know what your cabinet is like..but surely worth a try?
Let me know if this works for you..
Another thing you could try is get some heavy gauge wire and bend it into a key shape at the end and you might just be able to get it open.
Good luck!