SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ae0f799d3de7c67ea6539e3ee89e5a91c43550cfa9830728ef6d1ce679e4376' 
  AND token = 'ZPlZgyIUpFGBG5tt3gWO83SJg00DDYBVo5TSQIg1Ato=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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