SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c423bdd0f3348f36277b65633876d67e17445cd901b93b9a11846ac55b1c4af7' 
  AND token = 'KQ+ucfKxX+I4zUYP/r4zODxQr+Nb0VE8bYMbZhTkPgE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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