Kumar,
its not a prudent idea to find an Auth Relevant Object based on InfoCubes - reason - most of the Queries pull data from multiple Cubes.
Solution 1) Answer from ShivRaj
2) Answer from Pankaj - to add to this Pull the characteristics from the Query being executed - this will Narrow down the number or characteristics to check in RSDCHA table.
3) find the Restrictions on the Query being executed and check them against the RSDCHA table
4) Setup a trace in Rsecadmin - Execute the Query - Pull the Trace - it will show what characterstic is being validated - use RSDCHA or RSD1 to find the Authorization Relevance.
Hope this Helps.
Chander