SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '449130b9cc52b9802333893586fb05bce89970803d6a4ea24a3e79ee2b72544f' 
  AND token = 'lxFEkCH+yuO1OwbfQtSVCFSoC+el/jwCsiicdxCzjFY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}