SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34fe58f0826af6d528f0066dfb1291aba5f34e5dcf0734c943491e8ea14170b8' 
  AND token = '5zs5fVaLsLZKqTt1TWinE3DMhwE8VkwcOFefzQLzLM0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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