SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff8396edc81c0063e172698bc1d141507f392ca93644b1af1399e687ad0fb06d' 
  AND token = 'IY9iyEFGhUSbl1WxWjUTU3JwBC1RaGQ0GzCcHXxlyVA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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