If you haven’t added the posts_where filter that is definitely why you’re not seeing any results.
Please have a look at the link I’ve posted twice now. In there Elliot explains how to use the posts_where filter with example 🙂
It does get added to your functions.php yes. The reason you need this filter is to modify WordPress core behaviour for meta_queries to do a LIKE search letting you find crew_0_blabla, crew_1_blabla etc.
