The date_added filters were added just to use that index and with a broad range, since there isn't a filter on date_gifted. You'll notice the date_added range is 30 days but the date_gifted range is 3 hours. We really only care about date_gifted but at this time there isn't an index on that field.
Even as I experiment with some query rewrites, the EXPLAIN ANALYZE always says rows=75. I'm *very* curious to see why it is using that value.