SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '57346976bad0c118d36e6932978a155b2351dae355e4e68ac822ab14d19d2c8b' 
  AND token = 'ur+gOYWlw793UrZCWgaNZHjuoYA9+O3OYoJXwpwvfHc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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