SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd238610fba5b917abd70ec57509a607b9c27e9af779344fa38ab474c7031726' 
  AND token = 'URAGhZWUjiwvOnlIjBSrGEVVc9Jh/ezE84uKKssW9uY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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