SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2e9e4dfb02a4d8e08df573d3b1bd1dfba3c9e3a87a4b9c88c961258f87263096' 
  AND token = '78VnQQ9nvzl7UvFA8Xm/qgaDyySUO53HmC+evdqHXKA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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