SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '66db0af621418e5d02e1f335a389bbf65a3f631a8734cb7a970a741b075c28a4' 
  AND token = 'c+PvXK4TO1CHYEGIUtzmJXueWIZpVD8ZK2bEgo9W1vU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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