SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73ada53de0962a70ae3f260d86342188b86028ac2a4bcbdd14febf15582a2f91' 
  AND token = 'L1Mmov3maIuncKFVM2k3HyOGIfLpjrdJTPiPzkniWK4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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