SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c691c0a7db738ce8b5e4ddbcb53528a6da8acf86678558b1e68cf7aaa091efc1' 
  AND token = '3IYlMfQL+2MezxvgEuwX+B6R601cJTV3gWUsyeqN7as=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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