SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0f959e77b43febe3247a9238a55cff356059ba75b1433f77dddbefd2a58faaf6' 
  AND token = '45i7OUqkqHhF6iQw+lPPUWWh1ve/DOp3nc3FOxNGUe8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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