SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '267150cd889678ee48e400592660abf2e123f8a5b158ee979da522715803f691' 
  AND token = 'vWJ519sjJqwL/zObbFpBOtjax3cako9u4CDs+AgM++Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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