Before printing check the shape of the inner part of the lock.
This key works with the triangle shaped element mechanism.
Measurements of the key blade:
My tests with PLA show that more than 3 perimeters is needed to withstand the torque resistance of the lock mechanism.
Infill does not play any significant role in such a small model..
This was a fast simple and easy openSCAD project (requires bosl2 library).
Project file is also attached.
The author hasn't provided the model origin yet.