Some remote data organized in a Mysql database should be replicated locally.
Only some tables and only a few rows inside those tables are important locally, so it is overkill to create a complete replica on site and synchronize it. Remote data will be transferred in json format and will be available locally with some delay.
What alternatives I have to store the received json objects ?
They are supposed to be no more than some hundreds a day, so they could be persisted on the file system too. Don't think it is a good idea create a database with the same table structure of the remote one relaxing some foreign key constraints for the data which don't need to be replicated.