SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9c2515be3480b1b5261e60e6f56478f266b64c7dca146526e9d2f78534d8e08' 
  AND token = 'Xl6cqM9mGfFqMg3u8Y6BWZYrhCHwOswsAg6LZZ6lVrg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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