SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c5921d47e855ea907a3acf958df14380480660b728dbd1a58bcb323a850a0ee' 
  AND token = 'DAdmCQwSQNyzvm3XNr96rskhGey6NidWgZnP7H9V9wg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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