SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5e1f31735382b7bb9bb08906cd287601ca486adb11fe48ae80f383e1fa7f718' 
  AND token = 'DPgn/HwYsVb8Y0MRx6kS/PQydA5uwIdOSTPUOZXWXL8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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