Export private and public keys from a PKCS12 keystore

Both keys into the same PEM file

openssl pkcs12 -in keystore.p12 -passin "pass:password" -nodes -out keypair.pem

Separate PEM files

openssl pkcs12 -in keystore.p12 -passin "pass:password" -nodes -nocerts -out private_key.pem

openssl pkcs12 -in keystore.p12 -passin "pass:password"  -nokeys -out public_key.pem