SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '239f8b3ad2373dca66302406fe181432ab2b1e907a2b373692ffae9c49201203' 
  AND token = '9oHxrmZv36TMepbzNkbmqtdGa4TtMRsnG1Wn7DkyhXE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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