You want array_contains():

where array_contains('cats'::variant, column2)

Rather than using JSON, you can use array types directly E.g.:

CREATE TABLE ts2 (obj_id INT, ts DATE, tags ARRAY, val INT);
INSERT INTO ts2 (obj_id, ts, tags, val) select 442243, '2017-01-01', ARRAY_CONSTRUCT('red', 'small', 'cheap'), 1;
INSERT INTO ts2 (obj_id, ts, tags, val) select 673124, '2017-02-01', ARRAY_CONSTRUCT('red', 'small', 'expensive'), 2;
INSERT INTO ts2 (obj_id, ts, tags, val) select 773235, '2017-01-01', ARRAY_CONSTRUCT('black', 'small', 'cheap'), 3;

The VALUES clause cannot use functions such as ARRAY_CONSTRUCT, but INSERT-SELECT will work. (You could also do this with JSON and a VARIANT type, but then you would need to tag the value with a key name, and use PARSE_JSON in the insert.)

Then to query rows that only contain exactly both tags you chose, use a query like this:

select 
  obj_id,
  tags
from ts2
where ARRAY_CONTAINS('small'::variant, tags)
  and ARRAY_CONTAINS('cheap'::variant, tags)
;