SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5473c18edb9b9158920df79cba7305bf6fc9bba9938301db9c9357c37aaeabcf' 
  AND token = '/izRkw2/0VnepnmvOauWwJ4f9DDrS05GurdEMNDsPdE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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