Best practices for relating NoSQL data to RDMBS
There are two ways I would approach this.

1.) Dump your json from Mongo into a tmp_retrieval_table in MySQL, then write corresponding db functions to perform the parsing / ETL to the schemata of choice in what ever fashion you see fit.

2.) Utilize MySQL's partitioning functionality. Where you could in deed sort the records by a specific key or timestamp.

MySQL Partitioning