SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b99b6d6475d0735e8ef90f1dbe75284f75265ad36b89f7c07f2b0c29e87f6f0a' 
  AND token = 'UJzJoXIp/r13bIrJc/B41ojJUHlihTShuM6EzFpBV4Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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