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 (
    69837, 69838, 70146, 70147, 70728, 70727, 
    70726, 70725, 70724, 70729, 70738, 
    70737, 70736, 70735, 70739, 70800, 
    72391, 72392, 73560, 73559, 73558, 
    73557, 73556, 73555, 73554, 73553, 
    73552, 73561, 74579, 74580, 74578, 
    75536, 79245, 79246, 79247, 82262, 
    82271, 82272, 82273, 82274, 82275, 
    82276, 82277, 82278, 82279, 82280, 
    82281, 82263, 82264, 82265, 82266, 
    82267, 82268, 82269, 82270, 82333, 
    82334, 82616, 82625, 82626, 82627, 
    82628, 82629, 82630, 82631, 82632, 
    82617, 82618, 82619, 82620, 82621, 
    82622, 82623, 82624, 84766, 84292, 
    84293, 84401, 84402, 84403, 84404
  )

Query time 0.00697

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": 81,
          "filtered": 100,
          "index_condition": "pfv.variant_id in (69837,69838,70146,70147,70728,70727,70726,70725,70724,70729,70738,70737,70736,70735,70739,70800,72391,72392,73560,73559,73558,73557,73556,73555,73554,73553,73552,73561,74579,74580,74578,75536,79245,79246,79247,82262,82271,82272,82273,82274,82275,82276,82277,82278,82279,82280,82281,82263,82264,82265,82266,82267,82268,82269,82270,82333,82334,82616,82625,82626,82627,82628,82629,82630,82631,82632,82617,82618,82619,82620,82621,82622,82623,82624,84766,84292,84293,84401,84402,84403,84404)"
        }
      },
      {
        "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'"
        }
      }
    ]
  }
}