How to access raw data in twig template using views table format
You can try to apply getValue() of the field handler on the result row, for example:

{% if view.field.field_name.value(view.result[key]) %}


Edit:

In a views table template row is not of the type ResultRow, so you need to get it directly from the view object using key of the loop {% for key, row in rows %}. 

See these questions for different views templates:
How can I get data from ResultRow object in views template and How to preprocess view field?