SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e03c64932ecbc6bf0d407558007ab7ccc08cdade0fc7dc7469218de772ff7f52' 
  AND token = 'BVcw1/ls9q55FmTYIQYiOkYesbd70ouyy5Y4BWYDuA4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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