SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '023ad9d98e1f63586ca4921486897929bb265acac8edf20717b8e4aa74605460' 
  AND token = 'UPvNyxrMkMoXG0LHqbVWCtG92iwQzsNivf+PTpJDHV8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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