SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b721f7ee1097cc81c9669898a02a40d30ffe3d0d5a7bf02451db1523b47203c' 
  AND token = 'RoYhZigeMrCLti4+LQNHKfDuQFepxDZVrvgBEDVpGWs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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