SELECT 
  text 
FROM 
  cscart_font_lang_data 
WHERE 
  lang_code = 'ko'

Query time 0.00012

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_font_lang_data",
      "access_type": "const",
      "possible_keys": ["PRIMARY"],
      "key": "PRIMARY",
      "key_length": "6",
      "used_key_parts": ["lang_code"],
      "ref": ["const"],
      "rows": 1,
      "filtered": 100
    }
  }
}