SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a83621c719a845b23a8c8c75fb14225a3dcc37330d2ff9320cb9d43d8fcbb43e' 
  AND token = '00CQGIL3WLyjrscoqyxvD5c6tNurJjv2nFCORkBjqQI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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