Reading this section of the Stack Overflow site it seems that there are some payment services to have quick answers in any Stack Exchange community: is this true?
No, this is not possible. You get quick answers by writing good questions and sharing your research/attempts. Bounties might work but you can only post them after 48 hours. All suggestions to implement 'payment for answers' have been heavily downvoted, e.g. Would it better the community if we got compensated for posts? Even with minuscule alt coins? As are any attempts to indicate urgency, e.g. An "urgent" tag for questions that need answers within minutes.
What you linked to is a way for a company or team to privately share internal knowledge among employees or team members. You pay Stack Overflow to host the 'community', but it does not offer support to pay colleagues or something.