SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0b3ac61fc72a3a1580094cb3a91e4af044340f36fa7bd9b6c25399974b8f76e6' 
  AND token = 'LTAbzSxvS1sVBNHvn97lA/4ZYIjmnM+C36IdSWFVfCw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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