SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2dbdecd05a4c293eb75522c857a575493a49ecca8ad728890f10c70219476b36' 
  AND token = 'IW5wjfF+VuZF6GbdSstqPsLddTMIt1OL7nOXJ3U9EdU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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