SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ab4dff2f960c109adfa83a9b85dc39fd5244aa3bde4f836d1c853977b0c8348' 
  AND token = 'JYSOsXn4rUHgxRmKH1rtjZ0nBzfNrnJuS58QGocKh7Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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