Wow 40's F. My advice is plant it in a seedling bag and take it outside during daytime and take it inside the house during the until your night is not below 60's. Use well drained acidic soil and wait for 2-4 months..

I have grown Miracle fruit from seeds, I rough up the outer coating, and plant in a miracle grow mixture. Have not had any trouble getting them to sprout. I live in zone 9b outside of Orlando. You could bring them in at night, with the cooler temps. I did not use any bottom heat and kept the soil moist but not wet. I have about 6 seedlings. The most important thing is to plant the seeds when they are fresh. Germination definitely declines with time.