Not that it would explode, but a discharged battery will take a lot of driving to recharge to be able to start the car next time. So it would be best if you take out the battery, and connect it to a charger plugged into a mains outlet. The charger should have a maximum current in Amperes of about 1/10 of the Ah capacity of the battery (so for a 45Ah battery a 4A charger should be fine). Lower current is OK. Keep it plugged in charging for about 24 hours (more if the charger has lower current then 1/10 of Ah capacity of the battery).
If you have a voltmeter, you can measure the voltage on the battery terminals while charging - charge it until it is at least 14.4V, and then 6 hours more. Put the battery back into the car - it should start fine.
Please also read this question: Reviving a vehicle that has been idle for a long time.