This is Mystery in Space 6, published by Mimosa (SA Magazine Co) +/- 1959.
It reprints the cover and the following 2 stories from DC Comics' Mystery in Space 51 (1959):
"Battle of the Moon Monsters!"
"The Man who discovered 'Earth'!"
24 pages, full-colour, newsprint stock cover and interior pages.
Here is the cover of issue 6 and DC Comics' original cover:
Mimosa Mystery in Space Series