SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '045ad1fb5193c632c96892be781d41463d9ccd5d976f99602a04c25839b26157' 
  AND token = 'QG12dKWmkxjq9JhwO9VRyZxSj78VFmowHhTkKwlZ8ro=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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