SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6da90cf711ed01f96601e5b20a74572306b392ee0d9560573475a3985bd7430c' 
  AND token = 'sWTSFrhnSPyO/9ecjY4rbcVaefIWl7VgR+XzdZ2aLJ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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