SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '33863b434e1b650a5e16de60a37766b1e017892d004b4f1c7731d805779f3622' 
  AND token = 'aLLR6dRXXoklFLNjyiBz+iMhSIGCHT+Y5WOgbdFVZVI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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