SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '69f000a2cdc621dd9d947e171fc45d59ec9715c89d75c6be3ec24c55195e915f' 
  AND token = 'sSzA9u5WJy+0xq+cDD1v9jKrZGKu0mIr/8CS5DnbQpM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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