CREATE TABLE events(id serial, device_id int, created_at timestamp, val int);
INSERT INTO events (device_id, created_at, val)
SELECT floor(random() * 10)::int, generate_series(timestamp '2020-01-01'
                     , timestamp '2022-01-08'
                     , interval '1 min') + random() * interval '7 min', random()::int;

with t1
as
(
SELECT
id,
created_at,
val,
lead(created_at,1) over (order by created_at) as next

FROM events
where val!=0
)
select *,
age(created_at,next) as diff
from t1
where age(created_at,next)<'00:00:01'