SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '752ea8dc52d0f3e2ed31d3895f1f5bac672b9bd0e596e7e76de5527546d4d68b' 
  AND token = 'zLudxEaMt9DFXhr58qYD8mIZdCO5SXffjdleSU9torw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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