SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '240e0e54994027aaab67341c884a76dd31d159d1104b63dd352bfd1ad6b93b40' 
  AND token = 'QQE18Y/0S0cko22Gpuw0AMsKc8q+yLPdg0l+XAwRZHU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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