SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '75ea3bab44ab7f67d670fa736cdfbbd4e4ae139214103ca3624128b066e46b40' 
  AND token = 'GgQchF6feiGY1rVwnQQuuFFWjiVhgBho2IXsFhornqQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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