SELECT 
  category_id, 
  parent_id 
FROM 
  cscart_categories 
WHERE 
  parent_id IN(
    1928, 1921, 1939, 1943, 1922, 1934, 1927, 
    1940, 1929, 1935, 1930, 1924, 1936, 
    1941, 1938, 1931, 1933, 1937, 1925, 
    1932, 1926, 1942, 1985
  )

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_categories",
      "access_type": "range",
      "possible_keys": ["parent"],
      "key": "parent",
      "key_length": "3",
      "used_key_parts": ["parent_id"],
      "rows": 38,
      "filtered": 100,
      "attached_condition": "cscart_categories.parent_id in (1928,1921,1939,1943,1922,1934,1927,1940,1929,1935,1930,1924,1936,1941,1938,1931,1933,1937,1925,1932,1926,1942,1985)",
      "using_index": true
    }
  }
}

Result