SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '638ff1a1d54dcde158cd871d35a002699fb2f93522505f20ed824ece79d2bcb0' 
  AND token = 'OE9xHkIe1S4KyVfSBiul7uro0OUmr2foD2xnOm/hE0E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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