SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '61b7b760b077eebc3b3dbef5c9b034beca2f6da68dc25cd4cdd97adffc99521c' 
  AND token = 'jIYTiuvB0mu6A8HISBMr6f+5KTBipaYrzY3xmMxjM+o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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