SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18670c380381830787f5029d1b986993178cdcdf6ffca3e2d4205851010257f9' 
  AND token = 'KouV1jdSvL1LVRuyGzVO4krEiS/QGCRrREVoP+vb8RU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00050

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}