SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e68198a6c41e6c56a65254c7af4abd6a56802410e4ccb292ee344a5236a15ffb' 
  AND token = 'HdGBfNlMWslsEhx0DorOh3HlcqgHNNdmlZanIhY6YjY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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