SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71ac9229297990b6fdef988fd664648087e0cecd838c07fc2491807cf391009a' 
  AND token = 'qODbQg9JHnHLEKVz3WIQCSqYAlNbiz8+bw1VBs6NLvQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}