SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d8c1b94e9cfe671e35251550806861d86e5d8775781d44460013c5a91f34874' 
  AND token = 'RvLFyrhPExppPhmzqYIudI2jazaFaPiWT1qpRHXjAzA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}