SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0e08a42e10cb18c4e99edf3ac9d382b63cc6d0a714251a0302d19558a2a79e51' 
  AND token = '5P0zwJI4ZFjVQQkpeJlHiTlVddXiUoNy+aGoudMOLf8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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