SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1386b163d36065eef04043f8c44423159a0ee9242fcef97e38758b5e7996163f' 
  AND token = 'UgN9hiZQBoP5JRop/p4uqpVoyAtu5YJcxeMawF6+gXE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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