Hello,
I am not the plugin developer, just a user, and I’m here to create my own question in a different ticket. However, I’ll answer your query.
It is possible to deactivate the index via this URL: /wp-admin/tools.php?page=imfs_settings
Revert keys: Revert to WordPress’s default keys.
I also imagine it’s possible to do it manually (with raw SQL), but I wouldn’t recommend trying that, so forget I even mentioned it.
For myself, given the importance and volume of my data and to ensure peace of mind, I would use wp-cli with this command:
wp index-mysql disable --all
After all this, you could have seen these options by checking the plugin settings or reading its main page.
Good luck! ??