SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c23551698692882847aceb097687dadf2e3afdefd40f6da4072e73f16fb22b29' 
  AND token = 'lpKwjv/sCGbmyKOEMeX30Wr1fXIZXCHqdxKRsEyD6B4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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