Prep the chicken legs. Pat the chicken leg quarters dry with paper towels and rub with olive oil. Combine the salt, pepper, garlic powder, paprika, onion powder, and cayenne (if using). Rub the mixture over the chicken legs.
Air fry the chicken. Follow the instructions for your air fryer and preheat it if required. Arrange the chicken in the air fryer basket, skin-side up, and cook at 375°F for 12 minutes. Flip them over and cook for an additional 12 to 15 minutes, or until the are crisp and browned. Look for an internal temperature of at least 175°F to 180°F in the thickest part of the thigh.
Serve. Transfer the chicken legs to a platter and let them rest for 5 minutes. Garnish with parsley, if desired, and serve.