Are you aware of any Prolific Academic/mturk alternative with Japanese and Malay participants (n = 300/country)? We are planning to run a cross-cultural study including Japan and Malaysia and might have the funding to pay each participant US-$1.50-2.00 to participate in a 10-12min online study. Ideally, participants would be 30+ years of age from the general public. Recruitment services such as those offered by Qualtrics would be too expensive.
With Lucid Marketplace you can select your sample and pay around $1 per participant.
One of my colleagues applied survey technic to young (students) in Malaysia and it was interesting that in a short term he gathered hundreds responses. It seems that it is still easy to drive people to participate in a research.