SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '961a7a5ff674e3fa1feb3a4f3de79ce43997610d93fdc105dd5532628f7c1a5c' 
  AND token = '4F4plNBMjzav1iiDVTYU+FkLl5aRrxs2jE3cpt0GlZk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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