Query Plan

 Nested Loop  (cost=1.11..3.23 rows=11 width=12) (actual time=0.038..0.062 rows=10 loops=1)
   Join Filter: ((v.val >= intervals.since) AND ((v.val >= (lead(intervals.since) OVER (?))) IS NOT TRUE))
   ->  Seq Scan on vals v  (cost=0.00..1.10 rows=10 width=4) (actual time=0.006..0.007 rows=10 loops=1)
   ->  Materialize  (cost=1.11..1.27 rows=5 width=8) (actual time=0.003..0.004 rows=5 loops=10)
         ->  WindowAgg  (cost=1.11..1.20 rows=5 width=4) (actual time=0.023..0.028 rows=5 loops=1)
               ->  Sort  (cost=1.11..1.12 rows=5 width=4) (actual time=0.013..0.013 rows=5 loops=1)
                     Sort Key: intervals.since
                     Sort Method: quicksort  Memory: 25kB
                     ->  Seq Scan on intervals  (cost=0.00..1.05 rows=5 width=4) (actual time=0.001..0.002 rows=5 loops=1)
 Total runtime: 0.140 ms