SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '00ed21e6bea9491ac63ec7fab7a1bb5e7f9c33921ffc64b205ece8e86465837d' 
  AND token = 'duBYJqiJpesonjF4mIjrHryKzML/0LzBkZIzXRy82j4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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