AIUI a judgment in one EU state can be enforced in any other, but issuing an EU-wide arrest warrant for non-payment of a civil judgment by someone neither domiciled nor resident in any member state is, IMO, rather unlikely. Even if one were issued, it would be solely for the purpose of bringing the person before the courts (generally in the form of an enforcement officer) to answer questions relating to their assets, in order to assess if/how enforcement of the judgment might happen.