SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1a6f78f3a4d5b0bfe4bfae205c62797c4105b08f18737af1af3d888ce0d4283' 
  AND token = 'TIhRKJPOHPMYIwOaeeGzw2L1Tg/yXWLsOjODwlwKGgs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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