Welcome to CruiseReviews, jdave222!
Costa Maya is a "fake" port in that it didn't really exist until Carnival Corporation helped the Mexican government build it as a new place to go. It is a dock with a touristy open air village that resembles the American idea of a Mexican village, with bars, shops, eateries, and pools. A mile or so south is a real Mexican village where you can also get beach time and pay a lot less for food and drink. This is a safe area. The drug stuff has stayed mostly to the north and west. I wouldn't feel unsafe in the Costa Maya area, but I'd probably book any tours with the ship and not locally if I was going off the beaten path. Although if just going to the real Mexican town I'd have no problem booking a little excursion privately for the surrounding area.