SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5236d27be0942212408896cee922cccb21011f0e807f7da94da049580fb75e2' 
  AND token = '6Xv71zOf41x6LQiP/CoMMgdkyAX961zoEDlY/I0aq28=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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