SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9d79ecc913ecf0fa175f153bbf0bf78b6cc0070401043d6b2b2577537adbe2a' 
  AND token = 'qxpYHvuxoKvtAGK6k5Q6iqViW4qTFpztE+zlpUsjyow=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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