SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '443f820691cee380a53e2d3b758965e1da89e83149142924e990985c97247dd9' 
  AND token = 'kh1IX9+mwXu1thEfeXvuGd+7xLlly55FlhUJuWX523w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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