Publication can be fast, but indexing in any case takes time

If you already have the title and abstract for your article, you can use the following tools from Elsevier and Springer to help you pick a right journal among those that belong to the respective publisher

http://journalfinder.elsevier.com

http://journalsuggester.springer.com

The output of these tools shows inter alia average article processing times and impact factors of the journals.

Once you make a short list of potentially suitable journals, you can check whether they are covered by Scopus here

https://blog.scopus.com/posts/titles-indexed-in-scopus-check-before-you-publish

and by Web of Science here

https://mjl.clarivate.com

See also

http://www.ams.org/publications/journals/notices/201710/rnoti-p1184.pdf

and

https://www.elsevier.com/physical-sciences/fast-publication-in-mathematics-and-statistics

for average article processing times in some of mathematical journals.

See this link

http://www.imvibl.org/dmbl/sci/2_sci_exp.pdf

Indexed journal takes time

In the area of Mathematics, one of the fast journals, is:

International Journal of Engineering and Technology (IJET) - UAE.

It gives the fast publication.