SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '49877cb6ed9583ea7d949e50743068d8a9a14c3e17cf62720c1a82455c0d8dcf' 
  AND token = 'pjpmIWlcmVgqhZ8FybwxYz3hZJ7TvUoAJMcrzXjc/rI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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