Can't delete WP Smush Pro

I'd like to remove the plugin WP Smush Pro from my network for the time being, but it won't go. The plugin is not active on any sites. I've tried deleting it from the dashboard, but it simply hangs, and then my session times out. I've tried renaming the plugin directory to disable it, but it still appears in the plugin list in the dashboard. I am hesitant to simply delete the directory until I know the tables that were written to the database will be handled properly. Can you advise please?