SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '894dfb5d05bd2e9207d5901b085e415b490a16648ebe27d9814d15ee0dc63a16' 
  AND token = '5r3eGCB1PIon1rRXDEBY/xgDSYsK44h+fxwr/kEZgiw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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