SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4cbf7fb189ec9ca659343096e79b6f0f24d4f3ae73d5b6f40f1708bbfa7a606f' 
  AND token = 'kDSKebRcJu7cC2oJCK1LnD0MHH+rPia/37TPMlRrnqA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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