In a mixing bowl, combine the olive oil, lemon juice, minced garlic, oregano, thyme, salt, black pepper, and red pepper flakes. Whisk the ingredients together until well combined.
Place the chicken breasts in a resealable bag or a shallow dish. Pour the marinade over the chicken, ensuring all pieces are evenly coated.
Seal the bag or cover the dish with plastic wrap. Refrigerate for at least 30 minutes, or up to 4 hours for more flavor.
Preheat the grill or oven to medium-high heat (about 375°F / 190°C).
Remove the chicken from the marinade and discard any excess marinade.
Grill the chicken for about 6-7 minutes per side, or bake in the preheated oven for 20 minutes, until the chicken is cooked through and reaches an internal temperature of 165°F (75°C).
Remove the chicken from the heat and let it rest for 5 minutes before slicing and serving.
Serve the chicken with a side of roasted vegetables or a fresh salad for a complete meal.