SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'e52c8e7788a10f6d58d2922cfc36584693333b120c45430d3229d1570b7c9878' 
  AND token = 'RlWsMAqg4P14kKlhzOQEklXcYHY6/5PjLG1figDQcBc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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