SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a944ddcd281f4df758a244625ecbee6f919be7f6d25cc2eb4635944f9562b36a' 
  AND token = 'hzXN8yTNhMNPnWjMvPhK3GgIr7ITe6Lw9SUftXOVkuk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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