I found a cheaper, app-controlled keysafe:
Now I have two of them. In the beginning they worked very well, but they sometimes have issues opening and closing. This way I thought I would be able to discreetly give control to my parents and to make it as easy as possible. But with an unstable app constantly reconnecting the two would even increase the awkwardness.
Right now I practise wearing cages and belts using a screw-cage which has a hex wrench instead of a lock. This way it can be removed easily in an emergency by doctors. Additionally I have a small hex wrench locked in the KeyPod which I carry with me all the time. This way I can easily unlock in an emergency, which gives me safety while wearing my chastity device and the effort to open it is enough to make me masturbate less.