SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23616449cbf24312693aec154ba4ce581523a9638a96c3e96ab3573d6e647550' 
  AND token = 'To4edQfkMQbiY//FkBSeOQSV+UuvR0hP3tfjr9EfDfk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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