SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b78d491455e455cbdd978a552f05d2499fdb9fa0d6049ec8b52fa8d41df2826a' 
  AND token = 'Wu9BtgUVDFfhO9ydBf3sToMbE67krikGITyEKyOaTVk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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