SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '97d519f5d7e363e9da4ede5cbfec8d2bff8982b39c0c57aa43033194439ff767' 
  AND token = 'DHBRMxHQTpYJ9YjbFWk/EL5PRnBigBCyEPdRmDHzPnE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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