SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '276bc580a966bc42a8d2bfccfbce04e854d7e3eb5adedfc9fb0037032b12f7b7' 
  AND token = 'x57gvUzBW/Z7hMY5YZJkwmV41l7CfYw5+7Eti+vjKAs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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