You have a (presumably) paying client that asks you to improve their database performance. You realise that the database is part of/set up by a 3d party software package. I'm going to assume that there is indeed a tangible performance issue and you have some ideas how to address it.
You have alternatives.
Your client is also that 3d party vendor's client ...
Why all the obfuscation? Your query boils down to:
WHERE userid = '3081217' -- why quotes? Isn't this a number?
AND price_is_settled = false
AND price_rejection_code_id IS NULL
Assuming price_id is defined NOT NULL (probably the PK), then count(*) is equivalent, a bit faster, and might allow index-only scans more ...