SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2bef36e5ab7579b2aaa285fe815a452dc8573aa5f13be561c8a46b554346d52c' 
  AND token = 'EZlqiiC9IyTA9b58rIr81v6lDFxyDNSrqgkQr3anexY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}