SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f8d25db02815681fe5eed1fa04e7975b8c2d3faa17a841b2df4a734ab95581b' 
  AND token = 'MSfDmh+I1F0ZU0lkBlKDkFnpBxGns6CLv8MJh/VOLgM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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