There’s

  class AmazonAffiliateLookup(models.Model, TotalCountMixin)

I guess that TotalCountMixin adds some triggers that maintain a count of the records in the table in a separate table (could or could not be a good idea, depending on the table size, relative frequency of ‘give me the number of items’ calls relative to inserts and deletes, etc, but might introduce a bottleneck on updating that count)

There also is:

  song = models.ForeignKey(Song, on_delete=models.CASCADE)

I don’t understand why that foreign key is there, but it can’t speed up inserts and deletes.

Then, we have:

  created = models.DateTimeField(auto_now_add=True, db_index=True)

I think creating an index is done to implement the equivalent of Redis’ auto-expiry.

Again, that may be suboptimal if there are few records in the database. DateTimeField also may be ‘too structured’ for the task at hand (it might needlessly parse year/month/day out of time stamp in nanoseconds, for example, or even do time zone calculations to convert a local time to UTC), but I don’t know. It would be helpful if the text showed the actual SQL DDL.