SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '84e8dae9cfa8da7f8988177684f091f314f63e2a3f68f8053604847cdb212759' 
  AND token = '0CRPMaY1RAh3ZxzwKAuX+61OCjrotkOnLFqrcumjEVs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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