I have a safe or a gun locker in my flat.

Its dimensions are:
From left too right - 1 cm + 0.5 cm for hole + 1 cm
From notch to right side: 0.6 cm
Dimensions of the door: 27.8 cm x 17.8 cm
Outer dimensions: 35.8 cm x 24.8 cm.
I tried to search for the model of tke key but couldn't find any information (because of the notch). I am sure that the key is double-sided and the lock has 2+3 or 3+2 pins inside. I know that there are 3+3 self-impressioning keys available on the market but 2+3 config with notch is very unusual.
I will try to give you any information that you may need to help me to identify the blank key model and, finally, open the locker.
Thanks,
Siemaeniu