SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6de3c0bca0963f8460074e6c151a52276b7855d80fa1417fd6f7b93a8d8caf59' 
  AND token = 'eGrWnJ5JiSMnTGJYrO8ojRZwiHfJdXO9lGpQEMRnchg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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