SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0bc83dffd0d88bf530bc854ea207dfce39f8b5f40f11e128692f6c62d4fcab35' 
  AND token = 'O2+t+fw89cCCO8XcAGKhKXmU3KUDVV3sF27E87qqLvc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}