SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f1631fdac4baddcf2f110bc1a59b2a4a3872a69a95daae85c147180e22622aae' 
  AND token = '5XcsHI/ohVBlPoMGp/QNGZ8y/63KQkZm0pyUY5ToNuE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}