Preheat your oven to 425°F (220°C). Line a large baking sheet with aluminum foil for easy cleanup and place a wire rack on top.
In a large bowl, combine the olive oil, garlic powder, onion powder, smoked paprika, dried thyme, salt, black pepper, and cayenne pepper (if using). Mix well to create a marinade.
Pat the chicken thighs dry with paper towels to ensure they get crispy. Add the chicken thighs to the bowl with the marinade and toss until they are well coated.
Arrange the chicken thighs skin-side up on the wire rack. Make sure they are spaced out to allow air circulation.
Bake in the preheated oven for 35-45 minutes, or until the skin is golden brown and crispy, and the internal temperature reaches 165°F (75°C).
Remove from the oven and let the chicken rest for 5 minutes before serving.