>>>>Index your Employee_Queue_Schedules by iActive_Flag and see if this speed this SELECT up. I hope you have index by cTrans_Employees_Queues_fk in Employee_Queue_Schedules.
>>>
>>>I don't want to add an index on this integer field which has only 1 and 0 values.
>>>
>>>We have indexes on every fk and pk.
>>
>>Then why no optimisation for this table?
>
>Because it doesn't participate in WHERE condition.

CREATE CURSOR cTest (Fld1 I, Fld2 C(20))
FOR asd = 1 TO 20
    INSERT INTO cTest VALUES(asd,TRANSFORM(asd))
NEXT
INDEX ON Fld1 TAG cTest
SET ORDER TO 
CREATE CURSOR cTest1 (Fld1 I, Fld2 I, Fld3 C(20))
FOR asd = 1 TO 20
    INSERT INTO cTest1 VALUES(asd,asd,TRANSFORM(asd))
NEXT
INDEX ON Fld1 TAG Test1
INDEX ON Fld2 TAG Test2
SET ORDER TO 
SYS(3054,12,[tte])
SET DELETED OFF
SELECT * FROM cTest;
LEFT JOIN cTest1 ON cTest.Fld1 = cTest1.Fld1 AND cTest1.Fld2= 10;
WHERE cTest.Fld1 = 1;
INTO CURSOR ccTest
MessageBox(tte)

cTest1 also doesn't participate in WHERE clause.