SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '13a68d43d3b343e73a8bab5e4c97de09ceab3976848558f094ac5bc7324407e7' 
  AND token = 'TnH42SKVMLj8fDmejl23flRVDTVxK+Zly4D+UOq13Zs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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