SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4641d88adc65e7bbf9b845eff1b32728c80b562558bddd25ac2651d810dcffc0' 
  AND token = 'QO2PXd4BN1+mVMtZWiz84508nDRbjIoAsz05hTcYnT4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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