SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '819c50772d90ef7ab44806375d0fec0fba412d142181c935c1d4d6c2f1b1f909' 
  AND token = '41AmbIz2ny3VbYzDK4UIjJj3Ond4g30RUt3ye22u9dM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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