Here is what you need to consider:
- Maximum number of partitions in MySQL 5.5+ is 1024.
- You can change number of partitions without regenerating numbers, although it requires rebuilding indexes.
- Partitioning speeds upqueries only if the query hits less partitions then you have available cores
If your query hits all or many partitions, then partitioing in this way will not help them much. There is also a chance that your setup is efficient, but hardware is not capable to produce result faster.