SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90f10dd832dcc0d3f299f78743a4587ba657f1536e8c0809dcb5658ed0fd93f0' 
  AND token = 'TnEg3Csr9STuLfK/dXEGkY6pfVRMdETYToehhSH7WaI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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