SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '826fca773018c75e3ac8aacbe239999ebae003a9f9e47c736884195aea4f5de2' 
  AND token = 'V8MF8izwn4njRxuIgua3D00oo30Y2m9o0uEdRcrXQbc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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