Is there any way to access orchestrator using API key, not credentials (login + password)

I have an orchestrator api-key, but cannot get access token, because there is no such api method:
login model requires login/email and password

Depends on which version is your orchestrator instalation, latest one, will take a bearer token for authentication but the method you show is for authentication so is natural that it would ask for username and password… see this for reference:
https://docs.uipath.com/orchestrator/v2019/reference#building-api-requests

I read this already today. So my question is in which way i can get authentificated using api key? There is no mention about api keys at all.
bearer token is not a orchestrator api key.

I mean do you want to get a bearer token without using credentials?

Yes, look at the topic:

using API key, not credentials (login + password)

just not possible in on premise instillation…

finally found the decision by my own:
must append rest api param to query
orch_host.com/api_method?api_key={orch_api}

actually, this way did not work without credentials:
when i logged out orchestator api became unaccessible