SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2bbe02cf7810cd1079b2753a42370f3a487156891ed39ab49299c2d382c09c92' 
  AND token = 'VKsj8ZDZBEIHFjV3MdRJx+VLBPesMklcUn+CTm1gqqw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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