SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a773d30c3f1cead8eb915c312f8cd480c5553120f0bfb789e7abbaf894e5834' 
  AND token = 'Itr7QRqQ54l3LLYmLM0AV/dzJ+kBgUyZPbV44Y6zeYw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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