SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '686c91494bf0fdb7e6f7101758ee024a0ebbb0496a1f4927b32bebf5763fadf9' 
  AND token = 'UIod3lR3VbfoYpzQ+sb29DlCZmNuC9B3nOBRByVmeWU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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