SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '67e8f0f9e3540bf532a3971dcf943107d0e4d4b9d3024020f7637a393787f91a' 
  AND token = 'PSN3zU4T2xdWoO47TxYYX5xLj7ht44Je23s8WFskmqQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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