Preheat oven to 400°F (200°C). Line a baking sheet with foil or parchment paper.
Pat chicken thighs dry with paper towels to ensure crispy skin.
In a small bowl, combine garlic powder, onion powder, smoked paprika, dried thyme, salt, black pepper, and cayenne pepper (if using).
Drizzle olive oil over the chicken thighs and rub in. Sprinkle seasoning mix evenly over the chicken, including under the skin if desired.
Arrange chicken thighs skin-side up on the baking sheet, leaving space between each piece.
Bake for 35–45 minutes, or until skin is golden and internal temperature reaches 165°F (74°C).
Broil for 2–3 minutes at the end for extra crispy skin, watching closely.
Let the chicken rest for 5 minutes before serving to keep it juicy.