SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be5b9659947f744832673951f684ec462ee1205fbb07184c5fe2c0db0da063e4' 
  AND token = '7CssqTzVPSKL9K+5kMvrCB9Com2rggf085J0BJKQWtA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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