SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad2cbe687240661a20d47673c441a7f2b01d33fed59751dca3bd89a5b517cc1f' 
  AND token = '7nJeTpEpyqKTeahkXuIqEmOZsfZnIB2W1yNl4bqc5eI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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