SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '73555ab8eda5427b2ca90891ba057791273c7581482eda41a89ab23fb1868956' 
  AND token = 'q85Z2P30ubebuK2uiIybkofn6IQ/YFfPgEvHW8ZqFRA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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