SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aa4cc91fc634719ddd4a24c835701e911a24504cb8352ebc6ea3465ce1278109' 
  AND token = 'XHt4Z4Zw5+NViTUkdsefmXnopZ5+tQJs85larEXOcLM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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