SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81f77ab42518f26163f0faeae62c436359d16ca154ef57aaebee197b20bebfef' 
  AND token = '4EtXjDmlhlJS/kb4HhBimc3EyOltJ1qraq65dGA0t4U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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