SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '17b0df7c8be3c37711736537f915d6f1d00989051e7181f5ba9308cd73530ce3' 
  AND token = '0D4GpoPjRJgkuVbcZmH35JI/SqCwFnNXxs5h9yH74bc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}