SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d1817b1550b613bf584de96f700d35dcf4f758b4e0fe407099788acd9d20eaa' 
  AND token = 'YC/jUSmFpUdu2ttHtpqzZakTTOU/vhnan/DbBT+fWeo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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