SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f919b22f3ac4ce225ae419609a98dec2ddf67f72e99642d8839aa6843812672b' 
  AND token = 'sCfAUlJVXv/SvOObY+uf5ODGlxWRgT7n8VgZesVLlq4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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