postgres sql query

query.sql

-- This is the result I want:
-- 
--  foo | bar | description
-- -----+-----+-------------
--    3 |   4 | two
--    1 |   2 | four
--    5 |   6 | five
-- 
-- Which I can get with this query, but can I do it
-- more simply?
WITH latest AS (
  SELECT
    foo,
    bar,
    MAX(created_at) AS created_at
  FROM my_table
  GROUP BY foo, bar
)
SELECT
  mt.foo,
  mt.bar,
  description
FROM latest
INNER JOIN my_table mt
  ON mt.foo = latest.foo
  AND mt.bar = latest.bar
  AND mt.created_at = latest.created_at
ORDER BY id;

schema.sql

CREATE TABLE my_table (
  id SERIAL PRIMARY KEY,
  foo INTEGER,
  bar INTEGER,
  description TEXT,
  created_at TIMESTAMPTZ NOT NULL DEFAULT CURRENT_TIMESTAMP
);

INSERT INTO my_table
  (id, foo, bar, description, created_at)
VALUES
  (1, 1, 2, 'one', '2016-06-28 14:40:00.574059+00'),
  (2, 3, 4, 'two', '2016-06-28 14:40:04.416476+00'),
  (3, 5, 6, 'three', '2016-06-28 14:40:07.733142+00'),
  (4, 1, 2, 'four', '2016-06-28 14:40:11.281644+00'),
  (5, 5, 6, 'five', '2016-06-28 14:40:14.616076+00');

WITH ranked as (
    SELECT *, RANK() OVER (PARTITION BY foo, bar ORDER BY created_at DESC) rank FROM my_table
)
SELECT 
    foo, bar, description
FROM ranked
WHERE rank=1
ORDER BY id;

Thanks!