SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6ed03ed60fdaf73258bd2218a9718165a0c1b43a60c17bd33f337199215019d' 
  AND token = 'VG9RO97eMNBLteLmWcpwej+w+D542mTNOlHhUiX/D18=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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