SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f1bfdf2d8124866da8d127431e79122d7dd12b8fb4beb7bb3f6c6c749039a83' 
  AND token = 'fAFxi5QL+riJgeTNKJh/gnIEZJzTzeRX/fBGszDb/jk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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