SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36e3806b4a8014a392b8e0a6dc5b4f4cbe2185089a3861ebacdbfb3694bba62c' 
  AND token = 'NTxJwPHjCqxEY16vK5n0QW1ptBAQJVXY7PsWmXrdfuM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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