No, it didn't do a full scan. The operator's the same, you can tell partially from the number of rows outputted and the reads done. It's still a scan, not a seek

p.s. It's not an ordered scan because there's no order by on your query, hence no requirement for the data to be in any particular order. Put an Order By <clustered index column> and you'll get an ordered scan.

Ordered scan = scan the index in order and preserve the order

Unordered scan = scan the index and don't worry about the order