SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ffa34e7bb00919356992e389cb17547abbd46e1783f16e807deff52e4324b1d' 
  AND token = 'CmW39LFvn9Oaaq2tWshbmGpOlHL6JVsmPBFC7RzNb+w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00065

JSON explain

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