SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '28958950e69e89aed22cbfcbd89eec2ad96bbf725b1183f2f7704c1471b6734c' 
  AND token = 'YcrXyWhbpbs1jIbJstTh+IYIEfLx2a9hzaSj9CYMdXo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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