SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e6fde5c3330d082f9925cff08164449d8797cdf469f6eb3ea36477fddf9d547' 
  AND token = '9yOES9339FTOHZ8RLcuj9Eh+3NBuCuoqVp0AgMcrYgE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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