SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '19346b9313a6624b4d8655181d08e0e36d96c79f2cb2baf9d8a375c4025c3550' 
  AND token = 'XEmfYmLYOsQBAVLN9FWave+hyhh1zqxjqTYo3KBdqVE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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