SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56a1043d1224024c778f31ae48824bfd38c80e637a212f367375f53c8ae4bae6' 
  AND token = 'G6qNypIOW34k8PIaMORELfQ5cTmavWTjvHtO0zRoxeA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}