SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a96cbc658df0f09eb3c6598f3ec57be7f6bb46be888db0999643801361f7aebf' 
  AND token = 'zhrXfcRRFlT3hTrVbV8mvywkGebTDjG7watgVej8Okk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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