SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'e81c82716215e3946c084ebf7eb0436b8b82a8b222071e8b58318a0e78742aae' 
  AND token = 'zhaqzK/V7Z4ZVe/QqSNMk6ZwEgXS+YfZG1Afac+xT04=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}