SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '347764c832ea78f480962f9e0202f2b9b49aa28c17a5ae82f16713335d419024' 
  AND token = 'Hvn0AkKgxV1QAKJtrimUBlPuEQVLaaDNvzBq5y2D+HE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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