SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d17471efb304cd890cd016cbfecf75e500564e95ea05ef57231ac71160aa0d3' 
  AND token = 'RINUd+n+T9RKw+itFNB7iVOz50uWlgQ3Bd0colBaunk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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