SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8291dcf605c6dae8f01a8b98ea29e9376ca93c076cfa2d6cfaef21397ffb0c79' 
  AND token = 'kqpqrp6KkWYWGFGIIt/htthiCiDO3SEnEGy8zDW9DKc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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