SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54ba0545f0af6046cfa0bd93892df809d611cb1e14751baa09a15fb3c6748412' 
  AND token = 'iBPl9Tskfxievs6BDQ7qmXfIeKr3nkrXaAPExxkaLug=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}