SELECT 
  pfv.variant_id, 
  pfv.position, 
  pfvd.variant 
FROM 
  cscart_product_feature_variants AS pfv 
  INNER JOIN cscart_product_feature_variant_descriptions AS pfvd ON pfv.variant_id = pfvd.variant_id 
  AND pfvd.lang_code = 'vi' 
WHERE 
  pfv.variant_id IN (
    70183, 70182, 70181, 70180, 70179, 70178, 
    70177, 70176, 71589, 71588, 71587, 
    71586, 71585, 71590, 71601, 71600, 
    71599, 71598, 71602, 72337, 72336, 
    72338, 74591, 74593, 75462, 75461, 
    79032, 79033, 80579, 80578, 81269, 
    81270, 81495, 81496, 84338, 84337, 
    84343
  )

Query time 0.03578

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "table": {
          "table_name": "pfv",
          "access_type": "range",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "3",
          "used_key_parts": ["variant_id"],
          "rows": 37,
          "filtered": 100,
          "index_condition": "pfv.variant_id in (70183,70182,70181,70180,70179,70178,70177,70176,71589,71588,71587,71586,71585,71590,71601,71600,71599,71598,71602,72337,72336,72338,74591,74593,75462,75461,79032,79033,80579,80578,81269,81270,81495,81496,84338,84337,84343)"
        }
      },
      {
        "table": {
          "table_name": "pfvd",
          "access_type": "eq_ref",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "9",
          "used_key_parts": ["variant_id", "lang_code"],
          "ref": ["dev_db.pfv.variant_id", "const"],
          "rows": 1,
          "filtered": 100,
          "index_condition": "pfvd.lang_code = 'vi'"
        }
      }
    ]
  }
}