SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b1b69ab378d793e97d79774039642d9571bec07077b5ce9fd718fef8b64e9b7' 
  AND token = 'v4qphcMh5MqfzXohJguflCh4heK+F3GEbzmP7/+On9w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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