Please note that the data of this table fits in one data page - therefore a table scan is nothing more than reading one page of data. And doing row-id lookups is definitively more expensive than a single page read.
When you add more rows, the picture gets different.
If you expect only one row to be returned in a table with say 70000 rows, then the index seek + row id lookup (for one row) is much less expensive than a table scan (assume approx. 357 data pages) used for the 70000 rows.
Best Regards,
Chris Büttner