i am not aware of mmt card, but the one that i got with idfc wealth is valid as long as the credit card is active. you might send an email to the dreamfolks team with your concern. they were quick in replying to my query.
The Dreamfolks card is not transferable and is valid up to the date of expiry mentioned on the card or until such time as the said ICICI Credit Card is valid.
Enhance your airport lounge experience with the all-new feature of 1 international airport lounge visit and 1 spa session at selected airports in India every year, through complimentary Dreamfolks membership
The USD 99 annual membership fee for Dreamfolks is complimentary. You will need to pay for the lounge visit charges for visits done over and above the complimentary visits.
The above are as per T&C. So there won't be any charges.