SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46947804fbf4be94159def1c7d7dba181ba12f0a9accb38ecd15ed57c16468ea' 
  AND token = 'VRdXUU/ppyIyI8ywyB/7QgPBcYgyIqEqLe4lWrm9EwI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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