Where do you see the recreation of the database? In the minidlna.log file?
The plugin is just a wrapper for the minidlna server providing access to minidlna’s options in Volumio’s UI. The behaviour you described is not initiated by the plugin.
It could be this happens because there is an error detected in the database. However, I am not sure if a database rebuild is not part of the standard behavior when minidlna gets started. If the latter should be the case: To my knowledge there is no (documented / known) option to force minidlna to refrain from doing so.
Maybe have a look at the minidlna.log file (default location: /var/log/minidlna.log) for possibly related error messages.
For testing purposes you may also stop the plugin, delete the .db file (default location: /data/configuration/music_service/minidlna/files.db) and start the plugin with a minimal set of audio files only.