SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '29462f96c3c5272ceeaf4505d104270c09b8379851e373dcb007fc2762bf1621' 
  AND token = 'SBKfIwWKelyE7qCt/TVMjtfiiTnXsXsWGT/I9Q8KVJ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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