SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74c506fcd4a78c8ac767196166eebcf7ff59b5254195eeac7d8b4ac2825fa3fa' 
  AND token = 'XHRBAN4HSKfntYX91S3MbGiFQsWXCSYdZuYO9zYUtQ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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