SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '551c99366f59d2e65e30499e484ce6c8846005be99ac3a7f340789e8379dd75a' 
  AND token = 'pOYiJcZUU5P1Q3TtNHvvbPSrFah2MQuyFS8MF/6sLy4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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