Depends on the opponents. Higher CR opponents will mostly ignore your AC so resistance is better (obviously higher HP, AC, and resistance is best).
Moon druid physical stats are mostly dump stats. It's not hard to get a decent INT or CHA. Low CR opponents will have lower AC so they're not hard to hit. You'll have better spells and beast forms available by the time you encounter higher AC opponents.
Missed that rangers aren't allowed. Warlocks are specifically allowed.