SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '740610a9762aaa80973399743d5f49c36354b2ac47915ff844207e10dd602590' 
  AND token = 'MG4EJCNIYG+ea41FnYe6ur3A0WqwEFQWag2XqMZNydQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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