SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec218e4eb516fb60a7027e5839115479b3c47239c4fda3d515dad38735bbcd20' 
  AND token = 'uTkD11eEeFBxGgguEJj/Nmk3P0VT+JX6/+4z9vhwk8Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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