SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'adc4fdbc5ce1f759580ac9e5182e5713ab32178a6074369436e46440a51de76d' 
  AND token = 'ibQ6583hSy1tGx0YSf/qDbv0LuFWPDlk5cQPUdRquqU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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