SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '28e95b977f8d76b557606eed0b81cede3a4a09a25c57e41db5feecf165c7a97e' 
  AND token = 'ZivSQkW1fhsSK3eBvH81QJTt+XHc/H6+ymVp69ZuN3U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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