SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '17ad579f97641bbae69363b66752798babdd406eb924dce39f3804402ea61d54' 
  AND token = '+HT13sQcMm2fKxYha5cuz9tqi3NFKbMfUwf9xZ/vhIY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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