SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b914fc210566cd4b01f72ee1adc9e9c435073304beb2dafebd8a8fb87c7198ba' 
  AND token = 'JotP3cgdxJ4ddUicTeTeq3Smuh6I+BSvhqODsqmHHaI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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