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 = 'en' 
WHERE 
  pfv.variant_id IN (
    68775, 68774, 68776, 69804, 69803, 70367, 
    70368, 70366, 72105, 72104, 72403, 
    72404, 72411, 72410, 72409, 72408, 
    72407, 72406, 72405, 72412, 72413, 
    72414, 73458, 73457, 73456, 73459, 
    73455, 73496, 73497, 75872, 75874, 
    75873, 77415, 78608, 78609, 81440, 
    81445, 81446, 81447, 81441, 81442, 
    81443, 81444, 82259, 82258, 84630, 
    84629, 84628, 84627, 84626, 84625, 
    84624, 84623, 84633, 84632, 84631, 
    84622, 86311, 86310, 86309, 84554, 
    84556, 84555, 84553, 84562, 84552, 
    84561, 84563, 84560, 84559, 84558, 
    84557
  )

Query time 0.02103

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": 72,
          "filtered": 100,
          "index_condition": "pfv.variant_id in (68775,68774,68776,69804,69803,70367,70368,70366,72105,72104,72403,72404,72411,72410,72409,72408,72407,72406,72405,72412,72413,72414,73458,73457,73456,73459,73455,73496,73497,75872,75874,75873,77415,78608,78609,81440,81445,81446,81447,81441,81442,81443,81444,82259,82258,84630,84629,84628,84627,84626,84625,84624,84623,84633,84632,84631,84622,86311,86310,86309,84554,84556,84555,84553,84562,84552,84561,84563,84560,84559,84558,84557)"
        }
      },
      {
        "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 = 'en'"
        }
      }
    ]
  }
}