If cell contains text wildcard - excel

I'm trying to use an IF statement to find a string of text with a wildcard in a particular cell. E.g.

=IF(OR(K3="Fixed Rate*", K3="Mobile Rate*"), "true", "false") 

I have also tried something like this:

=ISNUMBER(SEARCH("Fixed Rate*",K3))

But everything seems to end up in "false". Ideally, I would like to find if a particular cell has either wildcard of Fixed Rate... or wildcard of Mobile Rate...

Does anyone know why and have a solution?

Thanks in advance!