SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0c5df046dfe1dff3872015f9be1e81294e520630717bfbcd22e5e5875907b26' 
  AND token = 'SGzOO6Yjt0oIGEJMbmxEaQKFzbxhnFGo4xq+vSSFHzU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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