SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '38641ef3cfc8ff829482417a389b074ce97343d533c2d4a6c3ec825bc35ae3ce' 
  AND token = 'J4/6W+CJWs8PPg84INi7BlIovaM887SsOHcj/92e63E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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