SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e5333a274a7afe84fa5d58b851e776dfb2fe98c78c830901c8dbcaa05acacee4' 
  AND token = 'hRu6REZYFrwh2oxCsgudsLYvi2DjRq2uQETBlVJo4hU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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