SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ee848b84e3bc3fe0ee42b4fe298811117d955c03ed65901dc23168a90af00d82' 
  AND token = 'Kjf6/oZuy6GSaL+oQwIkA56TGwlrd54YuljWEmjPoIU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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