SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f960b4b0a7a63f45a82f928336ca5bfc8938ac9dd4bad79256f1a7339a4c3ee' 
  AND token = 'hkhWJmMw43zRUglPpIZaDGir6XkRVwAyp+mGAeCvWjw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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