SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5bb6686bb32b8aa6f189e901eb4b5ec21add5bbf9af1a747418886979d00fee7' 
  AND token = 'w3MfDvprYzfUA7ve8dAV9xHGB9TqAcCL4vR//Hn1PtE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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