SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29d367070446303063415cf70ec89f062e771aed4de6dcfe5e762fa573d2bf0a' 
  AND token = 'A6sqSnsG0SCSaaNnzMHu2sQE1uG/KmcBSzDhHZ18v4k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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