SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3d02788965a17a61a1405cc39461f46ec5a397d5a64c89b986a2aeea5a9e3ac' 
  AND token = 'FVCAqWONIZYpPlvzK8PwDxWv/AKVmfH1fIZVJrTwgXQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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