SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '997c1f2db35e1b231cd7b9ff2f913564675b76d8482e682bf8d795a6fa64f7fc' 
  AND token = 'D/5MVDgreKnruV4snMOtvmwqhYApd1B4Bt5sfxyHrYs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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