SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'dd9dba48b78c0145aa1ce704a3d22efd02252805cee2b00779c5b39d56aa0618' 
  AND token = 'qRgaGp9VydOWgPl+N/n27B9HHQezz3lId8G3zSUUV2E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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