SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'd606531beb5924ea77b2d03a111b97cf801bd99ad12d43f7d57baa21a7343381' 
  AND token = '340ZqRF83JA6KimJZ7WxtDNK6xqbd7F7+/lX8IO5u8Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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