SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e73863bb5398e79c2e57e0a386aa6568e0a22c8e61c598c0725b422c3523ca6f' 
  AND token = '8HgvZj9s+TgQtbC/fjwfukIYLeOUGMJQF4LVnpj+oEg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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