you are likely to find Key in/at/on Idea. Idea is related to Dream. Dream is a synonym of Heaven. Heaven is related to Air. 
Gym is related to Fit. Fit is a synonym of Suitable. Suitable is a synonym of Favorable. 
Key --AtLocation--> Idea <--RelatedTo--> Dream <--Synonym--> Heaven <--RelatedTo--> Air 
Gym <--RelatedTo--> Fit <--Synonym--> Suitable <--Synonym--> Favorable 