SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '3a226273fe2f5415bc77d9577b44ac2145e93d3ff46cf3d4e726e757be806e69' 
  AND token = 'NuapKA++lZX/uchJu6RojxuW6hn616bNVZ9NU3Bqouo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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