SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ccc271d901ae37480fd9ad24291236935a034351f95ced32d4c2a0667743c1db' 
  AND token = 'KUwfvQypTDAOxdsAvfIj+oTP0lIDLlfWdA8sdQN7Ov4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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