[Answer]-Django queryset update performance and optimization

You saying that you are deleting but in your code you are updating the rows rather than deleting. Aside from this, the format you are using in the first snippet is the way to go.

To increase performance you can use index_together with owner, enabled and is_active fields (note this adds some load while adding items).

But, as @Selcuk commented, if you aim performance, go use some serious database backend like postgresql.

Btw, take a look at db optimization docs Django offers so you can learn some tricks for future implementations ;).