SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'e6326163f57986a67e80126be23d6a900e6840257afcf016c7eef7f1370360ef' 
  AND token = 'ShAZeGi+tBzbYd5KyXkF6opg9MoXhcB/1HVlgR09S/0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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