SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b9e4e28f93d08241ac4c2f63d4f80fd66d9434a2600d3dc02be3a271e3b0fab' 
  AND token = 'NPgbE/Ko3I3+R+a7Awub8ej+/uTTvDpe/ZxgZp0v4Lo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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