SELECT 
  storefront_id 
FROM 
  cscart_hybrid_auth_storefronts_providers 
WHERE 
  provider_id = 2

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}