Postgres fetch exact value when satisfied all conditions
I think this does what you want:

select *
from product p
where opid = 1 and opvalue = 1
and not exists (
  select *
  from product x
  where x.info = p.info
  and (x.opid != p.opid or x.opvalue != p.opvalue)
);


https://dbfiddle.uk/?rdbms=postgres_12&amp;fiddle=1efcb7a125d52c27b2c386307d37da5b