SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a04702f8798f1e344a7e4c437bd41a4ee4894df9c57d0cbdbb948c2869ee893d' 
  AND token = '8eZtHP+j7gDEb4i1u8oxps88fwlVa/RTLm0eSgLT124=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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