SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '4c8d914ef1a5224cb9daebfd260ae01256c167a6617da726b6fbe608c436e498' 
  AND token = 'IuCjPlSQQtA5l0kjo39FozxfDuHkvawEpEFj9XrUoPs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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