SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '64326e10ae8f68b20b00192b42ab554e02adb32863321ef9c5f2023fbe9d4c0c' 
  AND token = 'pwqKbmDXUjpaLFhipfH7YVP9YGZjJU9wAvnsRG7zAvA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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