paragraphs_update_8018 takes very long time to finish
Disclaimer: act on your own risk!

After looking into what this update exactly does, I decided to execute it without maintenance mode. It worked without any problems. It depends on your situation though. You have to make sure that nothing interferes with the tables in question (no editors editing paragraphs, no automatic content imports/updates etc.).

Note that drush updb automatically enables maintenance mode, you have to disable it explicitly.

Of course generally speaking it's not a good idea to disable the maintenance mode during drush updb and problems may occur.