Resolution:
Using as-admin you can check if any given query filter condition is performing an index scan or a table scan. 

Sample syntax :

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as-admin > join space 'space_name'

as-admin > show space 'space_name' query filter "space_field='5'"

Output : IndexScan

  Member Name |Scan Type  |Index Name         |       Estimate Cost|

---------------------------------------------------------------------------------------

Seeder-1-1       |IndexScan | sample_index       |                   1|

-------------------------------------------------------------------------------------- 

IndexScan : Query run across the indexes

Output : TableScan

Member Name |Scan Type  |Index Name         |       Estimate Cost|

---------------------------------------------------------------------------------------

Seeder-1-1       |TableScan| sample_index       |                   1000000|

ScanType :

 TableScan : Query run across the table (complete space).

 Estimate Cost: numbers of tuple query scan through ((in this case all the 1000000 tuples)).