Bring a large pot of water to a boil. Cook gizzards in boiling water for 30 minutes. Drain.
Combine flour, seasoned salt, black pepper, garlic powder, paprika, and cayenne pepper in a shallow plastic container; snap the lid on and shake until well combined. Add gizzards to seasoned flour; snap the lid back on and shake until evenly coated.
Place beaten egg in a small bowl. Dip each gizzard in beaten egg, then return to seasoned flour. Snap the lid on and shake one last time. Let sit for 5 minutes.
Meanwhile, preheat the air fryer to 400 degrees F (200 degrees C).
Place gizzards in the air fryer basket and coat the tops with cooking spray.
Cook in the preheated air fryer for 4 minutes. Shake the basket and coat with more cooking spray to cover any chalky spots. Continue cooking for 4 minutes more.