SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78141f8f8db87119fcd48c6a3eb38befe4bbfd85707583dc160d825fdc1514e3' 
  AND token = 'Gp8LIq5svp0Ex7SBc0hUMIBDOCTMjqj7emS1swiDG00=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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