SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '81868be88022567bebc144879e8b992cd743da9daa932a1689f9af98789a8e72' 
  AND token = 'qXJjjnUIM9hFoFiHqEzJePwxv14RYjZupLU04N9GP6k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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