SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '341d03ede426139ce23217f58d63c57e921f9161c4b45066381b0ae6c6fd5edf' 
  AND token = '5iME6jOA4b8lCsGzsHRglOtBXQOMUz4jejw9uXSXfBw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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