SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31cd3bb3408703b143504d04512758a79404de8e7cb01aebaba9222ba0f94500' 
  AND token = 'mL45qcOJc720PFMXPrxqgGAtwdvgtJcqtb8WKJY8Di4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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