SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '455cde8d6ce8415b7936c847d1286b83913c188800789104bece9d7cb013570e' 
  AND token = 'UxuHYnJdUKK/9MfadmZW3KNqe91lK4wo+cVwV5olhH0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}