SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '841a962acb643ef4cbfdcafca3f7dfcae8b83361dbae8692a029cc701a94dc8e' 
  AND token = '8pI3qMFn3LV0dxJkQhcJsmoTZJC46JUz6KKs086YoK4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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