SELECT 
  addon 
FROM 
  cscart_addons 
WHERE 
  addon = 'sponsored_contents'

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_addons",
      "access_type": "const",
      "possible_keys": ["PRIMARY"],
      "key": "PRIMARY",
      "key_length": "98",
      "used_key_parts": ["addon"],
      "ref": ["const"],
      "rows": 1,
      "filtered": 100,
      "using_index": true
    }
  }
}