SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '618edc2adf8513a297c634aba47f6ee651d25db91481878538032ca4a15f1a52' 
  AND token = 'EQG3e/rYqoPBVUHhNToCidmqqF+RkpgaunNU+UWhRAY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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