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 (
    70022, 70021, 70020, 70019, 70023, 70018, 
    70045, 70044, 70043, 70042, 70041, 
    70046, 70072, 70071, 70070, 70069, 
    70068, 70067, 70073, 70066, 70082, 
    70081, 70080, 70083, 70079, 70874, 
    70875, 70878, 70879, 70999, 70998, 
    70997, 71000, 71019, 71018, 71017, 
    71020, 72052, 73980, 73979, 73978, 
    73981, 75178, 75177, 75176, 75175, 
    75179, 77913, 80712, 80713, 80714, 
    80715, 80884, 80885, 80894, 80895, 
    80896, 80897, 80904, 80905, 80906, 
    81002, 81003, 81004, 81005, 81006, 
    81007, 82704, 82705, 82707, 82708, 
    82709, 82710, 82711, 82712, 82713, 
    82923, 83069, 83070, 83071, 83072, 
    83073, 83074, 83075, 86410, 86411, 
    86413, 86412, 87216, 87215, 87214, 
    80109, 80108
  )

Query time 0.03071

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": 93,
          "filtered": 100,
          "index_condition": "pfv.variant_id in (70022,70021,70020,70019,70023,70018,70045,70044,70043,70042,70041,70046,70072,70071,70070,70069,70068,70067,70073,70066,70082,70081,70080,70083,70079,70874,70875,70878,70879,70999,70998,70997,71000,71019,71018,71017,71020,72052,73980,73979,73978,73981,75178,75177,75176,75175,75179,77913,80712,80713,80714,80715,80884,80885,80894,80895,80896,80897,80904,80905,80906,81002,81003,81004,81005,81006,81007,82704,82705,82707,82708,82709,82710,82711,82712,82713,82923,83069,83070,83071,83072,83073,83074,83075,86410,86411,86413,86412,87216,87215,87214,80109,80108)"
        }
      },
      {
        "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'"
        }
      }
    ]
  }
}