SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '24ca50388a0df00429bb2d8af54e75c0adfe93e0814c272400236eb37d908cb0' 
  AND token = '8uxSgvgUpenGIkH7/r1HSJuSHeErD2CktK2rVGrAqjQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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