SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dbdb3bca2c47a5cb8f6c1e8d6bad3675e77faee228eb55adb96aa80180e45a5a' 
  AND token = 'P3JujgLaP+3jSDanmCuJEM5TT/Y1qrBlKWSWUTCaogI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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