SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73fbfb20b106a242a8cd82482e83c7688e0239eee6b222594e8c5eab6f56a7af' 
  AND token = 'xXEkweU3scvhhcIIZWVstTxDeXTOsh2vjAP9VWD3lqM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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