SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35f06bd45eb10f47f137dd001ba668b2b0189cc9af175b428cb5bed109ac0d81' 
  AND token = 'rQcA/sLr8V87k8uMhpXgSxPIJX52xMS+LBHH4UJlKtM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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