SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6d538ac8ca774789bb9ab454d3e291566c2099201fbca9e3ebcc6b49bea37dd' 
  AND token = 'TjrTPB8mIQiD+7+jRAUe9TmMA+1ozZqeebQdPQ1EnTo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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