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 (
    68347, 68346, 68345, 68344, 68343, 68348, 
    72131, 72130, 72794, 72795, 73300, 
    73301, 73426, 73427, 73425, 73481, 
    73480, 73563, 73562, 73926, 73925, 
    73957, 73956, 73955, 73954, 73958, 
    74498, 74499, 74497, 74981, 74980, 
    74979, 74978, 74982, 75200, 77945, 
    77943, 77944, 78622, 78621, 78651, 
    79176, 79177, 79178, 79182, 79183, 
    79184, 79185, 79186, 79187, 79232, 
    79233, 79234, 74407, 82455, 74412, 
    82456, 83984, 83985, 87716, 87715
  )

Query time 0.00450

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": 61,
          "filtered": 100,
          "index_condition": "pfv.variant_id in (68347,68346,68345,68344,68343,68348,72131,72130,72794,72795,73300,73301,73426,73427,73425,73481,73480,73563,73562,73926,73925,73957,73956,73955,73954,73958,74498,74499,74497,74981,74980,74979,74978,74982,75200,77945,77943,77944,78622,78621,78651,79176,79177,79178,79182,79183,79184,79185,79186,79187,79232,79233,79234,74407,82455,74412,82456,83984,83985,87716,87715)"
        }
      },
      {
        "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'"
        }
      }
    ]
  }
}