SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '7038789054cc2417d64f55151d4bdfaa3da1520d3599a4014c4225519bdf1c60' 
  AND token = '7NTDWqv2BWhNou80OVxhspkS72fMPhELZfldyWDSiVc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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