SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d83f204691903c22db007bad5949f2fe88abe4057cd660c1ea35c31b39c789a' 
  AND token = 'hll7YpBK14kKbN7WID2eprCmlBifvGalhoJaNNo6b0E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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