SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c635da493c9867cda94bcf5aac98ca58d0e030f44e4ab8b79a94a039257d47be' 
  AND token = 'YEo+0FyM5QoEoJLGNS2ODS8wXRYS6kuo5F9yMqVJmRA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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