SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55b413a0ed6c2aa5b442de30d02383adb992cc6f837908ba95848917afacdae5' 
  AND token = 'jFNL+28pjd7bgRnBAuFhKsNd01xSE8KNpEVwxISMZXU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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