Hi Abhi,
you should check if the queries are the real bottleneck or there are other factors affecting the time for serving a single file.
We know nothing about your server so the first ideas are, option (a):
- give https://docs.moodle.org/25/en/Performance_recommendations a read;
- you should tune your DB server to serve the queries as fast as possible;
- update your Moodle instance to a supported stable version;
- you could off-load the PHP stack from serving the file by using X-Sendfile.
Option (b) is:
- Carefully read http://danmarsden.com/blog/2012/11/01/managing-scorm-content-in-moodle-2/
- Deploy your SCORM content outside Moodle and publish it as an External Package: the files will be served statically by your web server and not via pluginfile.php which is charged to protect each bit of your package by those users not enrolled in that course.
HTH,
Matteo