SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6afe4e39b038b34f4758e1a00156a973ba74fc36f8a72bd359a67cbdd2c4790f' 
  AND token = 'tEYoIx0tVLZhvwaA+TRPO2Jgz1lj2hir7YTr3CMP6Vk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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