Of all my EOS lenses, for the shooting scenario that you outline, I would use the 35/1.4 the most.
In fact, I bought a Fuji x100s for this specific shooting purpose, and that is a consideration that you might also entertain.
But, in the meantime, these samples might assist you, taken in Low to Very Low Light Levels, Available Light Portraiture:
The 24/1.4 (at F/2.2)
“Drinks with Friend”
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The 35/1.4 (at F/2.2)
“Street Mimes”
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The 50/1.4 (at F/1.6)
“Bride's Maid”
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The 85/1.8 (at F/1.8)
“Woman at Window”
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The 135/2 (at F/2)
“The Lamp Post will not divide Us”
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The 24 to 105F/4L IS, to show the value of IS (i.e. little or no residual Subject Motion Blur from the ambient exposure in shadows) the shot was pulled at: 1/5s
“Selfies”
WW