SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7571d82ecf3194f4d30696b8fc4bdb32b386c329e7053730bdf7dc4bec074d0' 
  AND token = '1SfGq0EgE+1mqfytGhAvs9ozbOSGzW5Pvb3OhBHtT8g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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