SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '64d7b3255eadeaf170c41dcc3934d9ba0b000988a7c1651f673875a75266b246' 
  AND token = '/TliwiZVBkTWk0DitQZAdi+xwbO+SXPrxTcImz1LplY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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