SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7848b3d248432c9c18902283266e8ba660a16fe95401bb4417ae559d77f189f0' 
  AND token = '8y7vhLjsvpKtOQMrurVsXwm5Nvuls+ZLA4n3xhT6OBM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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