SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '381fd4da8a6e49a8bf5c8169d031d963205c983729a2d7c9afeba84efdf06312' 
  AND token = 'WwyzJNgYceB5P4SP1aGmuumr4G9xWOYCiZS0jYjckpc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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