SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef8f57dd84d5fdf37e04cfcec6e4f0aa0b20a7266b940be25f41470e759d7023' 
  AND token = 'dPHeyXrBBPDBbO0ez/9jzseFd/DjBAA8WBPnyE0xijY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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