SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c67df109abf12d91d7c6d6652688200f77453831579197a9d39054bd2ffecf40' 
  AND token = 'KmWgDyJRkxEZEGu4VcHqaVdTNt8bCl1c5EMLjkMeVk8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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