SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'dbc0e50950dfed861e7744707d21c51eaf170b12c6f9f23c7c82b13c834835a0' 
  AND token = '2UWnUJX3VlpG7B2oYY0faBoIjOL4sQblgSThYhPGPNU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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