SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d018737c421eb21acc5602f641edb19e04bb5a4ab6dde9a20661274ade95751' 
  AND token = 'IItRQ78y+RuhF4hse9HIJTB9KbrRIeCgoeilwme0gjQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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