That would be fine, however the key does exists. When same code, same
system, but the .exe built to be x64 it runs like a charm. 

32bit and 64bit Windows executables read different keys using the same
registry path. The 64bit executable can read keys from the 32bit part
of the registry, but is has to use the WOW6432Node path.
Maybe this will help: https://support.microsoft.com/en-us/help/305097/h
ow-to-view-the-system-registry-by-using-64-bit-versions-of-windows