SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '89a1c2b3720e181620c030baf829b034ff3f429e1ae606006a37f56c47200908' 
  AND token = 'jhjA3xf1V0MVlFVVdpzsu40vBN/PxaWdqNHZQ+SW4lk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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