I don't understand why you used the = Character in that way as it seems unnecessary, but if you entered find mode (manually or in a script) and specified: *"="* as your search criteria, you would find all records where there is an = character somewhere in the field. If you make that an Omit request, you'll find all records where that field does not have this character.
A late thank you for your suggestion.
Do I have to make a find request for each field? (There are 3 different fields where the "=" is found)
That will depend on the results that you want to get.
If you want to find only the records where all 3 fields have this character, use a single request and specify the same criteria in all three fields.
If you want to find any record where at least one field has this character, use three different requests.
The same is true to omit records with this character.