SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6846c9398cdf3f610943dabba3c3e922e4e8c32ac591343adf87db088a4ac9c' 
  AND token = '50Kq7AaPd+7RbLSAdG9lAOeydCvkNCetDqVKAGhHQoQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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