Sandbox

SELECT 
  c.product_id AS cur_product_id, 
  a.*, 
  b.option_name, 
  b.internal_option_name, 
  b.option_text, 
  b.description, 
  b.inner_hint, 
  b.incorrect_message, 
  b.comment 
FROM 
  cscart_product_options as a 
  LEFT JOIN cscart_product_options_descriptions as b ON a.option_id = b.option_id 
  AND b.lang_code = 'en' 
  LEFT JOIN cscart_product_global_option_links as c ON c.option_id = a.option_id 
WHERE 
  c.product_id IN (400) 
  AND a.product_id = 0 
  AND a.status = 'A' 
ORDER BY 
  a.position

Query time 0.00078

JSON explain

{
  "query_block": {
    "select_id": 1,
    "filesort": {
      "sort_key": "a.position",
      "temporary_table": {
        "table": {
          "table_name": "c",
          "access_type": "ref",
          "possible_keys": ["PRIMARY", "product_id"],
          "key": "product_id",
          "key_length": "3",
          "used_key_parts": ["product_id"],
          "ref": ["const"],
          "rows": 4,
          "filtered": 100,
          "using_index": true
        },
        "table": {
          "table_name": "a",
          "access_type": "eq_ref",
          "possible_keys": ["PRIMARY", "c_status"],
          "key": "PRIMARY",
          "key_length": "3",
          "used_key_parts": ["option_id"],
          "ref": ["multi_vendor.c.option_id"],
          "rows": 1,
          "filtered": 72.80000305,
          "attached_condition": "a.product_id = 0 and a.`status` = 'A'"
        },
        "table": {
          "table_name": "b",
          "access_type": "eq_ref",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "9",
          "used_key_parts": ["option_id", "lang_code"],
          "ref": ["multi_vendor.c.option_id", "const"],
          "rows": 1,
          "filtered": 100,
          "attached_condition": "trigcond(b.lang_code = 'en')"
        }
      }
    }
  }
}

Result

cur_product_id	option_id	option_type	required	multiupload	missing_variants_handling	status	position	option_name	internal_option_name	description	comment
400	32	I	Y	N	M	A	1	Patient Name or Code	Patient Name or Code (Required)*:	<p>Please enter your patient's name or code (required field).</p><p> After adding this first prosthesis to your order, if you need to order another type of prosthesis for the same patient, you can use the MULTIORDER menu available at the bottom of this page.</p>	Please enter your Patient Name or Code (Required). If you need to order another type of dental prosthesis for the same patient, you will find the Multi-Order menu at the bottom before validating your basket.
400	170	I	N	N	M	A	2	Doctor's comments for this work	Doctor's comments for this work	<p>You can specify information for this order, such as extrapolating the distal cervical limit of the 26 by 0.5 mm.</p>	You can specify information for this order, such as extrapolating the distal cervical limit of the 26 by 0.5 mm.
400	158	C	N	N	M	A	5	Delivery in 3 days:	Livraison dans 3 jours