SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4dff1d05c9778c51ca1814597c4f47ab4d7821c97a5974511293a915f748fb3' 
  AND token = 'TxYHMnR00xf42WMMxDtkC1SuyaIXsUvpyeKuEuLa9hA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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