SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '68c4480936091b9f458d4f485f09df4d261802121a51f6841b2543011dd0ddf1' 
  AND token = '96rJFv65KzzRJ58MplqAVCwH8rvWUFywW9IGj7Kxf/8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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