SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35c2a3355984d48b5f719fac9a2cd539390b171d9577b5a9edc327e342eb9646' 
  AND token = 'hDHv/DeuSmtucZcqyLKHGqW0ZI9qRo0bhiE09KYq544=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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