SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '40ec5d963bcfd993561ec246a47c1393dfa1356278afa10df8accfec4600cfc5' 
  AND token = 'XkkZUZcd/oEQDHS9xoaoXIawT+3LOrTmXLHymy8qC2U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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