SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4861c9e763a0dff5280e4bb862f073df73468c1efc2d7ac23eef63b31c97539d' 
  AND token = 'c+BKkT7NzB1jqXYlend+IyenlLODp6hovJ+qWFj5BtQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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