Can a hypothetical question be in past tense? Please see my example
Put simply: yes.
A hypothetical is just supposing that something is true so the often proposed hypothetical "what would it be like now if the enemy had won the war" is perfectly fine and, in fact, a very convenient example.
In slight deviation from the question: As @CopperKettle said, your example is not technically a hypothetical, but that doesn't affect the answer, just a note on the side.