SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '64cdf6ee52ba51a06f401761923deb8e8194c377f129f2b036ae05a142e7b8f4' 
  AND token = 'DNmH/Q+1zewjQh5atWvoVDQ03OwLmDlMtC+82+gifTo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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