Yes- try this formula:
=SUMPRODUCT(--(A1:A10="x"),--(B1:B10="y"),C1:C10)

The -- you see are unary operators that cause Excel to evaluate 1 when
a cell in A1:A10 is x and when B1:B10 is y. Other cells in those range
evaluate as zero when they do not match. The SUMPRODUCT multiplies the
rows in C1:C10 by 1 or 0 to derive the sum.