SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a2db97270ecbe79580867c935fa316950f6d35642d181933c57972586021951e' 
  AND token = 'KeWCj0XIThDhSOFgoJPmWMwqLpxIcPtHZmTtjVMKZ+s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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