Please take a look at the Key File Editor Manual.
Somewhere at the beginning I’ve linked to an older portable version of LO.
LO updates come very frequently. In one version it might work, in the next one not.
This is the reason why I decided to link to a version which I know of it’s working.
If that does not work you can import / export key files manually (without macros).How that works is described in the manual as well.