SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc83335b58042271d93f8414a097a56044884ba31856799942cc59d7a48709db' 
  AND token = '1wf2M3U0elAqOMb3viwHf5/+5//satJ0wpVm9OUCMa8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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