SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a8a818b1e5968d6aaa5356824708e1dd3e6b6e014661942d511466912d0236d' 
  AND token = 'jZapYjvvAPqZLhErYBYGKsjGZ5/XKo10ZCwbpoZMzWs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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