Unlike other proteins that have a specific internal temperature measured with a meat thermometer to see if they are done FoodSafety.gov recommends cooking until "Cook until flesh is pearly or white, and opaque". Shrimp start out light gray and transparent. As they cook they will become opaque, and white or light pink. It's important not to overcook shrimp or it will become dry and rubbery. They should still be slightly soft and only need 6-7 minutes total to cook in the air fryer.