SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15e46fc1e1899213a8d20bc251ed7f9d85a48031cfb5e88bbe5414b961c2ca96' 
  AND token = 'rbUFnVYJ20PqEn2VnhYweZeik0ugyQIlJJIINOcaNGM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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