SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59c8cd1223adf33b12480298aecf7161b50533c825615f5ded42a74d5b96b93b' 
  AND token = 'LDUf2eBSE+L8UUhWrZzNs/N/a1Hx5qjFBjJy+v9asgE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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