SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'efcef625b602d78e0d105c3af2ac187d37c421e18a80f5b6f913dd80299d4a56' 
  AND token = 'ncDswOEuKH1KQ/uqgFSQkvxD4WVJxpdLky6nq+bp1ZM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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