If patreon-creator-id is not saved, then post locking options will be totally disabled. It means that the plugin was not able to acquire creator id from Patreon using those API credentials.
If you have entered your credentials correctly, all i can think of is that there is something that possibly prevents your website accessing the API. This may be something to do with your host, the firewall on the server or anything similar.
First make sure the credentials are exactly correct and everything is there - no spaces copied at the start or end of any credential, and no issues with special characters not being copy/pasted correctly due to your browser etc.
Then, visit the plugin options page and refresh the page. If the site unlocking option doesnt become available, it means that the plugin is not able to contact Patreon during plugin initialization.
At this point you could contact your host and ask them. Its also possible that aggressive caching (like opcode cache) on host side is preventing the page from showing its recent state and hence option remains locked.