SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '468cdf37724aa774ff5ef4775964cacd99430a15076bce0c30071aebaf86d9e4' 
  AND token = '1/UgTA3/7Z59sSk7QPUZq1mOMzvdC18LR5ULyTDC7E4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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