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 (
    68953, 68952, 71329, 71330, 72042, 72041, 
    72058, 72057, 72059, 72070, 72069, 
    72071, 74219, 74968, 74967, 74969, 
    74981, 74980, 74979, 74978, 74982, 
    74986, 74985, 74984, 74983, 74987, 
    75945, 75944, 75946, 75947, 75948, 
    75949, 86913, 86915, 76698, 76697, 
    76701, 76700, 76699, 76702, 79197, 
    79196, 80251, 80252, 80250, 80613, 
    80617, 80612, 80618, 80619, 80620, 
    80621, 80616, 80614, 80615, 81996, 
    81998, 82000, 81999, 81997, 84373, 
    84372, 85938, 85947, 85939, 85940, 
    85941, 85942, 85943, 85944, 85945, 
    85946, 87006, 87007, 87008, 87009, 
    87010
  )

Query time 0.00606

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": 77,
          "filtered": 100,
          "index_condition": "pfv.variant_id in (68953,68952,71329,71330,72042,72041,72058,72057,72059,72070,72069,72071,74219,74968,74967,74969,74981,74980,74979,74978,74982,74986,74985,74984,74983,74987,75945,75944,75946,75947,75948,75949,86913,86915,76698,76697,76701,76700,76699,76702,79197,79196,80251,80252,80250,80613,80617,80612,80618,80619,80620,80621,80616,80614,80615,81996,81998,82000,81999,81997,84373,84372,85938,85947,85939,85940,85941,85942,85943,85944,85945,85946,87006,87007,87008,87009,87010)"
        }
      },
      {
        "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'"
        }
      }
    ]
  }
}