SELECT 
  cscart_bm_snapping.grid_id as grid_id, 
  cscart_bm_snapping.block_id as block_id, 
  IFNULL(
    dynamic_object_content.content, 
    default_content.content
  ) as content, 
  IFNULL(
    dynamic_object_content.object_id, 
    default_content.object_id
  ) AS object_id, 
  IFNULL(
    dynamic_object_content.object_type, 
    default_content.object_type
  ) AS object_type, 
  cscart_bm_block_statuses.object_ids as object_ids, 
  cscart_bm_snapping.*, 
  cscart_bm_blocks.*, 
  cscart_bm_blocks_descriptions.* 
FROM 
  cscart_bm_snapping 
  LEFT JOIN cscart_bm_blocks ON cscart_bm_blocks.block_id = cscart_bm_snapping.block_id 
  LEFT JOIN cscart_bm_block_statuses ON cscart_bm_snapping.snapping_id = cscart_bm_block_statuses.snapping_id 
  AND cscart_bm_block_statuses.object_type LIKE 'pages' 
  LEFT JOIN cscart_bm_blocks_descriptions ON cscart_bm_blocks.block_id = cscart_bm_blocks_descriptions.block_id 
  LEFT JOIN cscart_bm_blocks_content AS default_content ON cscart_bm_blocks.block_id = default_content.block_id 
  AND cscart_bm_blocks_descriptions.lang_code = default_content.lang_code 
  AND default_content.snapping_id = 0 
  AND default_content.object_id = 0 
  AND default_content.object_type like '' 
  LEFT JOIN cscart_bm_blocks_content AS dynamic_object_content ON cscart_bm_blocks.block_id = dynamic_object_content.block_id 
  AND cscart_bm_blocks_descriptions.lang_code = dynamic_object_content.lang_code 
  AND dynamic_object_content.object_id = 4 
  AND dynamic_object_content.object_type like 'pages' 
WHERE 
  cscart_bm_snapping.grid_id IN (
    1, 2, 3, 4, 5, 6, 9, 10, 11, 12, 13, 15, 14, 
    65, 66
  ) 
  AND cscart_bm_blocks_descriptions.lang_code = 'fr' 
ORDER BY 
  cscart_bm_snapping.order, 
  cscart_bm_snapping.block_id

Query time 0.00093

JSON explain

{
  "query_block": {
    "select_id": 1,
    "read_sorted_file": {
      "filesort": {
        "sort_key": "cscart_bm_snapping.`order`, cscart_bm_snapping.block_id",
        "table": {
          "table_name": "cscart_bm_snapping",
          "access_type": "range",
          "possible_keys": ["grid_id"],
          "key": "grid_id",
          "key_length": "4",
          "used_key_parts": ["grid_id"],
          "rows": 22,
          "filtered": 100,
          "index_condition": "cscart_bm_snapping.grid_id in (1,2,3,4,5,6,9,10,11,12,13,15,14,65,66)"
        }
      }
    },
    "table": {
      "table_name": "cscart_bm_block_statuses",
      "access_type": "ref",
      "possible_keys": ["snapping_id"],
      "key": "snapping_id",
      "key_length": "4",
      "used_key_parts": ["snapping_id"],
      "ref": ["multi_vendor.cscart_bm_snapping.snapping_id"],
      "rows": 1,
      "filtered": 100,
      "attached_condition": "trigcond(cscart_bm_snapping.snapping_id = cscart_bm_block_statuses.snapping_id and cscart_bm_block_statuses.object_type like 'pages')"
    },
    "table": {
      "table_name": "cscart_bm_blocks",
      "access_type": "eq_ref",
      "possible_keys": ["PRIMARY"],
      "key": "PRIMARY",
      "key_length": "4",
      "used_key_parts": ["block_id"],
      "ref": ["multi_vendor.cscart_bm_snapping.block_id"],
      "rows": 1,
      "filtered": 100
    },
    "table": {
      "table_name": "cscart_bm_blocks_descriptions",
      "access_type": "eq_ref",
      "possible_keys": ["PRIMARY"],
      "key": "PRIMARY",
      "key_length": "10",
      "used_key_parts": ["block_id", "lang_code"],
      "ref": ["multi_vendor.cscart_bm_snapping.block_id", "const"],
      "rows": 1,
      "filtered": 100,
      "attached_condition": "cscart_bm_blocks_descriptions.lang_code = 'fr'"
    },
    "table": {
      "table_name": "default_content",
      "access_type": "ref",
      "possible_keys": ["PRIMARY"],
      "key": "PRIMARY",
      "key_length": "18",
      "used_key_parts": ["block_id", "snapping_id", "lang_code", "object_id"],
      "ref": [
        "multi_vendor.cscart_bm_snapping.block_id",
        "const",
        "multi_vendor.cscart_bm_blocks_descriptions.lang_code",
        "const"
      ],
      "rows": 1,
      "filtered": 100,
      "attached_condition": "trigcond(default_content.object_type like '')"
    },
    "table": {
      "table_name": "dynamic_object_content",
      "access_type": "ref",
      "possible_keys": ["PRIMARY"],
      "key": "PRIMARY",
      "key_length": "4",
      "used_key_parts": ["block_id"],
      "ref": ["multi_vendor.cscart_bm_snapping.block_id"],
      "rows": 4,
      "filtered": 100,
      "attached_condition": "trigcond(dynamic_object_content.lang_code = cscart_bm_blocks_descriptions.lang_code and dynamic_object_content.object_id = 4 and dynamic_object_content.object_type like 'pages')"
    }
  }
}