SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0f3e3e91f61d6944550df779d643dd3a558ab1c0a957864c6605f20b2c20db55' 
  AND token = 'dUPDFSBFI7pKqEU/7FwdrMi09aiy0PXnwWRpmleepBA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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