SELECT 
  cscart_languages.* 
FROM 
  cscart_languages 
  INNER JOIN cscart_ult_objects_sharing ON (
    cscart_ult_objects_sharing.share_object_id = cscart_languages.lang_id 
    AND cscart_ult_objects_sharing.share_company_id = 1 
    AND cscart_ult_objects_sharing.share_object_type = 'languages'
  ) 
WHERE 
  1

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "table": {
          "table_name": "cscart_languages",
          "access_type": "ALL",
          "possible_keys": [
            "PRIMARY"
          ],
          "rows": 2,
          "filtered": 100
        }
      },
      {
        "table": {
          "table_name": "cscart_ult_objects_sharing",
          "access_type": "eq_ref",
          "possible_keys": [
            "PRIMARY"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "share_object_id",
            "share_company_id",
            "share_object_type"
          ],
          "key_length": "159",
          "ref": [
            "_testcscart.cscart_languages.lang_id",
            "const",
            "const"
          ],
          "rows": 1,
          "filtered": 100,
          "using_index": true,
          "attached_condition": "((`_testcscart`.`cscart_ult_objects_sharing`.`share_object_id` = `_testcscart`.`cscart_languages`.`lang_id`) and (`_testcscart`.`cscart_ult_objects_sharing`.`share_object_type` = 'languages'))"
        }
      }
    ]
  }
}