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 (
    70010, 70009, 70008, 70011, 70007, 70124, 
    70125, 71511, 71510, 74226, 74227, 
    74936, 74935, 74934, 74937, 75146, 
    75145, 79285, 79286, 79291, 79255, 
    80734, 80735, 80736, 80737, 84405, 
    84406, 84407, 84408, 84418, 84419, 
    84420, 84421, 85235, 85236, 85237
  )

Query time 0.01230

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": 36,
          "filtered": 100,
          "index_condition": "pfv.variant_id in (70010,70009,70008,70011,70007,70124,70125,71511,71510,74226,74227,74936,74935,74934,74937,75146,75145,79285,79286,79291,79255,80734,80735,80736,80737,84405,84406,84407,84408,84418,84419,84420,84421,85235,85236,85237)"
        }
      },
      {
        "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'"
        }
      }
    ]
  }
}