SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cd3a8fcaad1f2d30b97b7be516dddffe343ad62ed5a7b3bc3d3ed3b5b7c5568d' 
  AND token = 'qHldHAkRlSd92MQHLkac5y2HtLCiBK0tQCK1Yt5xMw8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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