SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '489bb41d555460683581932ef29c35ae79e5ba46a07c4782937ff0e8e7376e25' 
  AND token = 'butGg7DKM4z41hmsjYAY5eiW7NOSnxP6gVBkBZrpENg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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