SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '59bbc4e794326f0a7ff53aff9da180216fa1d5f79866914c3fdc8999ea1f6afa' 
  AND token = 'IElbQogWdNa9GFkMOIPYAzRlsPIJd8xAalFDFIH6as8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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