SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ecedcf663dde6dea64b551d2af4ba08f8b2a93f7648a0d0621be9495b137a966' 
  AND token = 'UFljz0JVdDC334/BhoJEAp1O1HzRAnHiAbgkS5yQWaQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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