SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'cab976f056170526cb1ed2eeaf0d010d27876b192ecd538446592a1a05ebb579' 
  AND token = 'vZoe9BoFss5LV25JWa8PVocuBv7av6ElWnVlT5eYxTc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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