SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '621e092048262481137bd8a259814e75acb56215eba024d2ef2495263bce26ce' 
  AND token = 'd/7lsw07H62/SVhWulbwKazhkgcxlRlOZd93IzDDR+s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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