SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '4155575e241d9c79e2f1184676699f1ca243801778b850353dac47a1aa0b4483' 
  AND token = 'Ll9DZkI7MMvM7oBz7nVQ6SYJGUGobJ53sGUOLwZSXIw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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