I’m not sure what you mean by “explain”. Paul is not attempting to explain the Eucharistic presence of Jesus in this passage.
However, it is the risen glorified body of Our Lord that is present in the Eucharist - the body Paul is talking about in these verses:
verse 42 imperishable
verse 43 raised in glory and power
verse 44 spiritual
It is a body no longer subject to our physical laws. After resurrection, Jesus could go through walls/doors (John 20:19); assume a different appearance such that His disciples did not recognize Him (Luke 24:13-31; John 20:11-16), etc.
To complete Nita’s answer, the Jesus we receive in the Eucharist is the resurrected Christ, God and man, soul and body, and that body is the glorious resurrected body that St.Paul calls “spiritual”. A true body of flesh and blood nevertheless, as Jesus Himself was anxious to prove following His resurrrection, by eating and drinking and by asking Thomas to put his hand in it.