SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fd3ec3385f50eca18ff8f56e1fd6d12159b4997bd963e5f96aad426b236045d9' 
  AND token = 'HqgqWSRaEK3uP+sd23JaF1tDQ41XFUrK1UOUORUtAuI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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