Most fuel efficient but high speed cruiser?

Looking for a car for long commute for my work. It’s around 150 miles round trip. The problem is I have a heavy foot and cruise around 130-135km/h.

Looking for suggestions for most fuel efficient car at higher cruising speeds?

Don’t care for how it looks, comfort etc. only thing that matters is fuel efficiency.

I was thinking of a civic or something but not sure how it fairs when cruising at higher speeds.