SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f64e6076c1c83ea74c4f19d23d55cc76d9f2833f55a532704b19bd6766c4739' 
  AND token = 'Bkbb+yTrqYHBhc9GikYusgZnvZ1X1Td4FpP5TvTqEuY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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