SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dddd3cc8d095b71fd60d0fee69e97032f9bfd603c2fe456489525b0685e14c9a' 
  AND token = 'x2IWK7XG2IfS7XF8qA+zWoF4bmls3OdVzF0zGNYyi58=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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