SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c4ddd39756edab7adb21c3cfb711622c57f78e0e4c4b59f1bf6d6267142a1aa8' 
  AND token = 'hIcYmYScBn9IJVO5MU0KhBWvqYH6y//ko3qGZH2VnXA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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