SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ecb44ef7213bac9e1e20752891e08a87c0f17306f246e0a332c06bd6f9bd53c6' 
  AND token = 'fT5mn+LsKupCFjM4YnpJjLdw6FmdfhkUmCcgkDzHRzk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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