SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '576cc0af4fbd440567725c7729a72bd04677cd5819632b970d9b3cedddf6fe4a' 
  AND token = 'SOyW+/H7aKW7FToKm9GUAzxGNLO9qoz+lso009Au8dM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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