SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '84364d5e56f014d700ac5563bda176176a23e1731e416d0ab990c29672338514' 
  AND token = 'Uip7V6xtuojsINcjkhz58pqip5/O31JfQCpSEYK+ZHk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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