SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7152dfa4b6eec05384c44c9509218dea18d1b5568947b64b30d38ee6f77b4f30' 
  AND token = 'uA9EC9++ZGp11VOHVGBYbRuYkiGeDoWMuok7j5jUUfg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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