Performs index query and returns index cursor which presents subset of index data which corresponds to result of execution of given operator.
Query that should be executed can be presented like: [[property0 = keyParam0] and [property1 = keyParam1] and] propertyN operator keyParamN.
It is supped that index which passed in as parameter is used to index properties listed above and responsibility of given method execute query using given parameters.
Multiple parameters are passed in to implement composite indexes support.
@param iContext
@param index Instance of index that will be used to calculate result of operator execution.
@param keyParams Parameters of query is used to calculate query result.
@param ascSortOrder Data returned by cursors should be sorted in ascending or descending order.
@return Cursor instance if index can be used to evaluate result of execution of given operator and
null otherwise.