The video of this play is found on the MLB Film Room (at 0:05).

This takes some explaining. There are several clues that lead me to believe this is the game on the card. The first is that he is wearing the a spring training jersey. The second is that his jersey number is not 8. After his major league debut in 2021, McKinstry wore number 8, even at spring training. Thus, this picture had to have been taken in 2020 spring training, where he wore number 73. The third is the All Star Game patch on his sleeve. This patch only appeared on Dodgers uniforms in early spring training, before games were canceled due to COVID. The Dodgers were set to host the All Star Game that year before it was canceled. The three spring training games played in July (when play resumed) did not have this patch. The fourth is the red colors in the background of the photo. The Dodgers were most likely playing a team whose primary color is red. This narrows it down to either the Reds or the Angels.

The Dodgers played each team once in early spring training. Both were day games. McKinstry played in both games. We only have footage of him playing in the game against the Angels. In this video, we can see everything matches: jersey, patch, sunglasses, bat color, batting glove color, sleeve color, etc. You may ask, how to you know it wasn't the game against the Reds? Well, McKinstry only had one at bat which was in the bottom of the 9th. The latest at-bat we have footage of for this game is in the top of the 6th where there isn't as much sun at home plate as there is in the photo on the card.

As a result, I claim that this photo was taken in the game against the Angels. Which at bat? No idea (McKinstry had other at-bats in this game).

I also believe that the photo on McKinstry's Gypsy Queen card from 2021 is this same photo with a few edits.