SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f0da51f7ab41c1c12300347dcb572efdf20b3b5b03dd339fe3b6dc7accde2c0' 
  AND token = '3sfoJ4kZsgZD8TFvFszpLjJyGVVAssk1f/eynsp33MA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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