SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1bc7c73bad477621c5c14fe4bf8101b386fb0d08ca642125d628e0ff77e850ba' 
  AND token = 'jJkKaooZjRJINrUiqNjWRxgubYpe+xMvOzcJZ4krTAg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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