SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08a718c20825999ab4857e498f6c8fff85db5ae648d9ea620d27755f54d6dc00' 
  AND token = 'nYThu+MqtFUhhpFLf1YGJ8+T+U88e3KN02gHY3Boq+g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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