SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a97b97bc1b09b99dabdd69a075b5a59515aba62f2067d9da421cd97b90f59f22' 
  AND token = 'DABKV/NhKAnWVMEzuw5vyuzyC1CJos4/rfCA6jr6/GY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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