SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b5faa0387b56a105d389ab7af87b485f2886c80ce05eb10245785082c7fb737d' 
  AND token = '641dPZSKDR7GnTTr1KigHWsylqtFd7stdCAOjOPBdo0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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