Specify timestamp format in queries

I’m using Influx 2.0 with v2 HTTP API and there is no simple way to specify timestamp format. V1 had a simple setting in the query as stated in:
but there is no similar option in current API:

I want the result in ms UNIX epoch format . There is a way using uint(), but since it has to be done in map(), it takes too much time in long queries, so I wonder if there is a way to do it without this.
I tried removing “Accept: application/csv” from the header but with no result. Timestamps are always returned as RFC3339.