SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '0cf852f7f71b39ac6cff36eb7e3bf3e6a2ab67f13977070bc959102078293841' 
  AND token = 'K8rt+mMmYxfD+AjQZT9JQvLUOT4WWlIfT00mTLh7Vew=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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