SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd649946346288cd66579d9f7d1cfa1308c04fd280d915a18654289b1d43246fc' 
  AND token = 'VBnmTiArQmDQSD2m7CFfdhKn4HwaqBokrj1qFL7eCLQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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