SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6ade81e74ce15f1de8c900d44920753f9017486aaf67a830967b48793cd94030' 
  AND token = 'PQtUC4fXBlIrtup6Wxefg/vBh4qJpuhNXqZru6DSqng=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00066

JSON explain

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