SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f42ce64f4f05aecbbf2e02a861474be4b4841fedec1bc0d7bb7242ea35c818f' 
  AND token = 'fBhhYZxdqYWrlyejUnKLba+2hmAjxRp102ZrH7LPGS0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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