Conditional Formatting Based on Time (Days) Lapsed

Attach a sample workbook. Make sure there is just enough data to demonstrate your need. Include a BEFORE sheet and an AFTER sheet in the workbook if needed to show the process you're trying to complete or automate. Make sure your desired results are shown, mock them up manually if necessary.

Remember to desensitize the data.

Click on GO ADVANCED and then scroll down to Manage Attachments to open the upload window.

I am asking you to attach a sample file from your side

Here is an example of what you could do if you put numeric values in row 40 and put the number of days prior to expiration in B41:B42.
Assuming that you would like the chart to retain its original colors until the date approaches the '30 days prior to' limit you would need two rules.
The rule for yellow could be similar to: =P3+P$40-$B$41< TODAY()
The rule for red could be similar to: =P3+P$40-$B$42< TODAY()
The rules are modeled in P3:S5 of the attached copy of the file.
Note: the file is being returned as an .xlsx as you profile shows you are using the 2016 version.
Let us know if you have any questions.