Add the Greek yogurt and kosher salt to a large bowl and mix well with a spoon.
Add the chicken drumsticks and turn to coat.
Cover the bowl tightly with plastic wrap, and marinate for 2 to 4 hours in the refrigerator.
Preheat your oven to 350°F. Line a rimmed baking sheet with parchment paper and place a cooling rack on top. Spray the rack with nonstick cooking spray and set aside.
In a separate large bowl, combine the flour, paprika, onion powder, and garlic powder. Mix well.
Remove a drumstick from the marinade. Pat lightly with paper towels to remove excess marinade.
Place the drumstick into the bowl with the flour, and coat it thoroughly with the flour mixture, then place on the prepared rack.
Repeat the process with the remaining drumsticks.
Drizzle the melted butter over the prepared drumsticks.
Bake for 35 minutes, or until golden brown and fully cooked through to 165°F.
