SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6cfbc9160c06402cea0188af9c97d53883a3434e106299748297c6280298575c' 
  AND token = 'pEGN47DuW/SsIEwj5PcqPZ6BnCs3rIVKSwt/PPaxQCk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00050

JSON explain

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