SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a368beac0136382517bbdc2c95647feb63955d7ce45015ae93f6b9a73bcb705f' 
  AND token = 'QK2L+6je7q4k0lYz2X/wOKtdeF/PyGt3iTIctilQc7k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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