SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03ddf3486580617fb5745beb1c5dd5faa89ce26c1f50e131730b0b62dfee4b16' 
  AND token = 'mcQ7SwcydfuChU7RfDZmyVti6oFCg0uVOpyXC3EPLvM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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