SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '61d3d566418088defd89761a1999b51f37e2360d1e6108a6c4cfa12b5bc15400' 
  AND token = 'ZKOAgALBuk+V1K1xr5mME3ZjNDxZkrwibv5v0N/g88g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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