SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08d42fb2e0608d9fa4068150f8cc322ec15df2720e0053ecaead18da0ae0a1ca' 
  AND token = 'P7jxMrkleyXJtsaBlD/dUDWXa99EhNhZhQAiWAh/Vu8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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