How to query a multi-value field for an exact value

I have a field that can have multiple values (i.e. "1111","2010","1015","12","1","X00000","X2010")

I want to search for records in which that field only has the value "1015" (it may also have values starting with X, but no other values)

For example give this two records:

record 1 : field = {"1015","1010","X00000"}

record 2 : field = {"1015","X00000"}

record 3 : field = {"X4010","1111"}

According to my needs, only record 2 will be correct.

How can this be achieved?