SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef6873f7595d5b68c54e451171b476d3eb874e8830ce35bcc9cbbbdf6196d0df' 
  AND token = 'JWdLYHFxP8hYaDJGPrGXlE+bWIxH8slsjSPy0tit8pM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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