SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '639fff0395d1032958dad713ebef8290494eb541aa967f74331025d648b57ade' 
  AND token = 'Rphhp9F6g34ydHcfh3iLHW/e7onmJynE2wZX+2GhzuM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}